CA2186794A1 - Automatic dialing mode selection - Google Patents
Automatic dialing mode selectionInfo
- Publication number
- CA2186794A1 CA2186794A1 CA 2186794 CA2186794A CA2186794A1 CA 2186794 A1 CA2186794 A1 CA 2186794A1 CA 2186794 CA2186794 CA 2186794 CA 2186794 A CA2186794 A CA 2186794A CA 2186794 A1 CA2186794 A1 CA 2186794A1
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- Prior art keywords
- tip
- dialing mode
- dialing
- ring line
- tone
- Prior art date
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Abstract
Automatic dialing mode selection techniques are utilized in the operational environment of a telephonic device connected to a tip-ring line. The telephonic device includes dialing mode assessment circuitry and dialing mode setting circuitry. The dialing mode assessment circuitry automatically determines the dialing mode supported by the tip-ring line. The dialing mode setting circuitry is responsive to the dialing mode assessment circuitry for automatically setting the dialing mode of the telephonic device to specify the dialing mode supported by the tip-ring line, such as pulsed dialing or touch-tone dialing. The dialing mode is automatically set at the time that the telephonic device is first connected to the tip-ring line, and the telephonic device retains that mode setting until the device is removed from the tip-ring line.
Description
Automatic Dialin~ Mode Scl~lior kg~Qund Of tl~e Invention The invention relates generally to telephony, and more particularly to techniques for selecting an approp~iate dialing mode for telephonic devices.
5 2. nes~ lionofPriorArt The dialing mode of telephonic devices must be set to specify the a~propliate dialing mode, such as pulsed dialing or touch-tone dialing. State-of-the-art telephonic devices do not include any means by which the capabilities of a given tip-ring connection may be automatically checked to determine the a~pi~liate dialing mode. Although 10 many tip-ring lines connected to the Public Switched Telephone Network are equipped to accept touch-tone dialing signals, other tip-ring lines will only accept pulsed dialing signals. The device user must m~ml~lly select an app,~liate dialing mode by setting a slide switch to a first position corresponding to touch-tone ~ lin~, or to a second position corresponding to pulsed ~ ling Telephonic device users are required to know the dial sign~lin~ capabilities of a given tip-ring line in order to select the proper dialing mode. Of~elltimes~ the dialing mode is not known, and, as a result, the slide switch is not set to the proper position. If the switch is set to pulsed dialing when the tip-ring line is equipped to implement touch-tone sign~ling, the device user will not benefit from the ~ltili7~tion of touch-tone 20 si~n~lin~- The telephonic device will take a long time to place an outgoing call relative to other telephonic equipment that the user may have employed in the past. If the user ~llelll~ to access services that utilize end-to-end touch tone sign~ling, such services will be rendered inoperative. On the other hand, if the switch is set to touch-tone dialing when the tip-ring line is only equipped to implement pulsed di~ling, the device user will not be 25 able to originate any outgoing telephone calls. When the dialing mode slide switch is not set to the proper position, the user may return the device to the seller because the device is perceived as having relatively poor p~_lrol.llance.
2 21 867~4 What is needed is a technique for automatically detc~ the dialing mode capabilities of a tip-ring line, and for automatically setting the dialing mode of a telephonic device to specify the appr~1iate dialing mode. Such mode setting should take place when the telephonic device is first connected to the tip-ring line, and the mode setting should remain in force until the telephonic device is removed from that tip-ring line. However, an option may be provided for the user to specify mode setting for the duration of a telephone call after the call has been established by the PSTN (public switched telephone network), thereby permitting the user to access interactive touch-tone services from a tip/ring line equipped to implement only pulsed dial si~n~lin~ for o purposes of call establishment.
y of ~he ~r vention Automatic dialing mode selection techniques are ut~ e~l in the operational environment of a telephonic device connected to a tip-ring line. The telephonic device includes dialing mode assessment ch~ y and dialing mode setting cil'cuilly. The dialing mode ~sessment circuitry automatically determines the dialing mode supported by the tip-ring line. The dialing mode setting circuill ~ is responsive to the dialing mode assessment circuilly for automatically setting the dialing mode of the telephonic device to specify the dialing mode supported by the tip-ring line, such as pulsed dialing or touch-tone lli?ling. The dialing mode is automatically set at the time that the telephonic device is first connected to the tip-ring line, and the telephonic device retains that mode setting until the device is removed from the tip-ring line.
Brief l)escriptior of the l)rawin~
FIG. 1 is a har.lw~e block diagram setting forth an illustrative embodiment of the automatic dialing mode selection system disclosed herein;
FIG. 2 is a flowchart describing a first sequence of operations implemented by the system of FIG. l; and FIG. 3 is a flowchart describing a second sequence of operations implemented by the system of FIG. 1.
l)etailed ~escription of the Preferred Embodiments FIG. 1 is a hardw~e block diagram setting forth an illustrative embodiment of the automatic dialing mode selection system 100 disclosed herein. Automatic dialing mode selection system 100 may be used in conjunction with, and/or incorporated into, virtually any telephonic device that is equipped to interface with a tip/ring line 121. A polarity guard 101 circuit is connected across tip/ring line 121. Polarity guard circuit 101 includes four semiconductor diodes in a bridge rectifier arrangement, and enables the automatic dialing mode selection system 100 to function properly, independent of the actual polarity of the DC voltages on tip/ring line 121. Polarity guard circuit 101 is coupled to a line switch 105, which may be an electronic, electromechanical, or mechanical line switch of conventional design. An optional mechanical hook switch 103 is present if, for example, the telephonic device consists of a POTS telephone (plain old telephone set). This mechanical hook switch 103 is coupled to line switch 105.
A first energy storage device is employed to store electrical power while the automatic dialing mode selection system 100 is in an on-hook state with respect to tip/ring line 121. In the present example, this energy storage device consists of an electrolytic capacitor 104 which is charged through an isolation resistor 102. Electrolytic capacitor 104 is selected to have a relatively high capacitance value of, for example, 1000 microfarads or greater, and as low a value of leakage current as is practicable. The DC
potential across capacitor 104 is coupled to a first input tçrmin~l 151 of a power supply control circuit 126. The DC potential across capacitor 104 is also coupled to a first input tçrmin~l of a second voltage sense circuit 135.
A second energy storage device is employed to store electrical power while the automatic dialing mode selection system 100 is in an off-hook state with respect to tip/ring line 121. In the example of FIG. 1, this second energy storage device consists of ~ ~ 21 ~6794 an electrolytic capacitor 108 which is charged through an isolation resistor 106. An ind~lctor having a relatively high impedance at audio frequencies may optionally be placed in series with isolation resistor 106 (or, alternatively, used in place of isolation resistor 106) to minimi7e the extent to which the combination of eleçtrolytic capacitor 108 and isolation resistor 106 ~ttenl-~te the audio frequency range. Electrolytic capacitor 108 is selected to have a relatively high capacitance value of, for example, 1000 microfarads or greater, and as low a value of leakage current as is practicable. A
rechargeable battery could be used in place of electrolytic capacitor 108 if desired. The DC potential across capacitor 108 is coupled to a second input tPrmin~l 153 of power o supply control circuit 126.
An optional power source 113 is coupled to a third input termin~l 155 of power supply control circuit 126. This power source 113 may comprise, for example, an AC
adapter that converts conventional residential AC current into a low-voltage DC current.
Such AC adapters typically include a power transformer that steps down this AC voltage (nominally 117 volts AC or 220 volts AC, depending on location) to a lower voltage level (e.g., 6.3 or 12.6 volts AC). The stepped-down AC voltage is applied to a diode bridge rectifier and the rectified DC voltage is filtered by means of an electrolytic capacitor.
Alternatively, power source 113 may comprise a rechargeable battery, a non-rechargeable battery, and/or a rechargeable battery combined with an AC adapter and battery-charging Cil~;uill~.
Power supply control circuit 126 selectively applies DC power to a main power 128 output t~rmin~l and/or a backup power terminal 130 based upon the presence or absence of DC power at each of the input termin~l~ 151, 153, 155 of the power supply control circuit. For example, if power is present at all ofthe input termin~l~ 151, 153, and 155, then power supply control circuit 126 applies DC power to both the main power 128 output and the backup power 130 output. However, if power is present at first input terminal 151, but no power is present at second and third input termin~l~ 153, 155, respectively, then power supply control circuit 126 only applies powér to the backup power 130 output and not to the main power 128 output. The backup power output 130 of the power supply control circuit 126 is coupled to a second input of the second voltage sense circuit 135. In practice, various combinations of transistors, diodes, other semiconductor devices, and/or logic gates may be employed to implement power supply control circuit 126. The construction of a suitable circuit for power supply control circuit 126 is a matter within the knowledge of those skilled in the art.
An electronic line switch may be employed for line switch 105 or, ~Itern~tively,line switch 105 may be a mechanical line switch. In the example of FIG. 1, line switch o 105 is coupled to an optional mechanical hook switch 103. Conventional components may be used to fabricate line switch 105 and mechanical hook switch 103. Line switch 105 is provided with a first port, a second port, and a control port for selectively enabling and disabling a commlmications pathway between the first and second ports. Polarity guard circuit 101 is coupled to the first port of line switch 105, and the control port of line switch 105 is coupled to microcontroller 115. The second port of line switch 105 is coupled to a voice hybrid network 111, and this second port is also coupled to a dial tone detector 107. The output from a DTMF tone generator 109 is coupled to voice hybrid network 111. The operation of DTMF tone generator 109 is controlled by microcontroller 115.
Voice hybrid network 111, DTMF tone generator 109, and dial tone detector 107 are components of conventional design, the details of which are generally known to those skilled in the art. For example, dial tone detector 107 may include an energy detector for detecting the presence of dial tone on tip/ring line 121. Dial tone detector 107 is coupled to microcontroller 115, and sends microcontroller 115 a signal indicative of whether or not dial tone exists.
A first voltage sense circuit 125 senses voltage on main power terminal 128, andthe second voltage sense circuit 135 senses voltage on voltage storage device 104. The 6 21 ~6794 first voltage sense circuit 125 is coupled to a first pulse generator 132. Upon sensing a voltage level above a predetçrrnined threshold, the first voltage sense circuit 125 activates the first pulse generator 132 to apply a pulse to the RESET termin~l of microcontroller 115. The first pulse generator 132 is powered from main power tetrnin~l 128. In this s manner, the combination of first voltage sense circuit 125 and first pulse generator 132 function as a power-on-reset circuit element that is responsive to voltage on main power termin~l 128 to reset microcontroller 115.
Microcontroller 115 may be implemented by a conventional microprocessor of a type well-known to those skilled in the art, and is coupled to an associated random-access o memory (RAM) circuit 122. Microcontroller 115 uses RAM 122 to store a mode control bit that indicates whether tone or dial pulse sign~lin~ is to be used. RAM 122 is coupled to main power 128 as well as backup power 130.
The operation of line switch 105 is controlled and monitored by a microcontroller 115. As previously stated, microcontroller 115 also controls the operation of DTMF tone generator 109. DTMF tone generator 109 is employed for the purpose of dete- .. i~ the dial sign~ling capabilities of tip/ring line 121, as will be described in greater detail hereinafter. The DTMF tone generator 109 is also used to place outgoing telephone calls and to access on-line interactive services that use DTMF si~lin~;.
The output of second voltage sense circuit 135 is coupled to a second pulse generator 143. When activated by the voltage sense circuit 135, which occurs when voltage sense circuit 135 senses a voltage above or below a predeterrnined threshold, the second pulse generator 143 applies a pulse to a reset input of latch 148. Latch 148 may be implemented using a conventional latch device. A set input of latch 148 is coupled to microcontroller 115. The output of latch 148 is concept~l~li7çd as l~resentin~ an "ID
bit". The value of this ID bit is forwarded to microcontroller 115 to indicate the time at which the sequence to set the dialing mode must be pe.ro~ ed.
7 21867~4 Microcontroller 115 may be coupled to an optional display device for providing an indication as to the dialing mode capabilities of tip/ring line 121, an indication as to the operations presently being pc.rolllled by automatic dialing mode selection system 100, and/or user plo.ll~ so as to enable a proper determin~tion of dialing mode at the proper s time, as when the telephonic device is connected to a new tip/ring line.
The embodiment of FIG. 1 is used in conjunction with telephonic devices that arebattery-powered, and/or powered from a conventional AC (~Itern~ting current) wall outlet. Such telephonic devices include telephone answering m~cllines, cordless telephones, fax machines, many present-day electronic telephones with enhanced fealules that require a steady source of power, as well as other types of equipment that may be connected to a tip/ring line. The embodiment of FIG. 1 also operates in conjunction with plain, old telephone devices, also known as "POTS" telephones, which do not generally include power source 113. If it is desired to equip a POTS telephone with enhanced features requiring the use of active semiconductor devices, these devices must thc.cfolc be powered up using energy extracted from tip/ring line 121.
In the case where automatic dialing mode selection system 100 is employed in theoperational environment of a POTS telephone that does not include a power supply, the system opc.ates as follows. Tip/ring line 121 is connected to a polarity guard circuit 101 which, in the present example, includes four diodes arranged in a conventional bridge rectifier configuration. While a POTS telephone is on-hook, in most cases, insufficient power exists to operate microcontroller 115. However, the bridge rectifier of polarity guard circuit 101 delivers a DC voltage of a given polarity to capacitor 104, independent of the actual polarity of the DC voltages on tip/ring line 121. These DC voltages may be used to trickle-charge an energy storage device, which, in the present example, consists of electrolytic capacitor 104 which is charged through isolation resistor 102. Electrolytic capacitor 104 is selected to have a relatively high capacitance value of, for example, 1,000 microfarads or greater, and as low a value of leakage current as is practicable.
An inductQr having a relatively high impedance at audio frequencies may optionally be placed in series with isolation resistor 102 to minimi~e the extent to which the combination of capacitor 104 and resistor 102 attenuate the audio frequency range.
The DC potential across capacitor 104 is used to power DC power supply control circuit 126 and latch circuit 148. The DC potential across capacitor 104 may also be used to power RAM 122 when RAM 122 is in a standby mode. In standby mode, RAM 122 retains the contents of its memory, but devices external to RAM 122 are not able to read the contents of RAM 122, nor are such external devices able to write to RAM 122.First voltage sense circuit 125 detects the presence of tip/ring voltage at the output of polarity guard 101. This voltage sensing circuit may include, for example, a Zener diode and/or a comparator device.
When the POTS telephone is off-hook, sufficient power exists on tip/ring line 121 to power microcontroller 115 and RAM circuit 122 using a power supply circuit con~i~ting of an isolation resistor 106 and a capacitor 108. An induGtor having relatively high impedance at audio frequencies may optionally be placed in series with isolation resistor 106 to minimi7e the extent to which the combination of resistor 106 and capacitor 108 attenuate the audio frequency range. Microcontroller 115 includes a DC powersupply input which is connected to main power 128. Upon the occurrence of an off-hook condition, power supply control circuit 126 couples this DC power supply input to capacitor 108 through a current limiting resistor 106. In the case of a POTS telephone, line switch 105 may, in fact, represent a mechanical switch hook. Altern~tively, the mechanical switch hook 103 of a conventional POTS telephone may be coupled to line switch 105, as shown in FIG. 1. The POTS telephone is placed in the off-hook condition by operation of mechanical switch hook 103 andtor line switch 105. In the off-hook condition, the output of polarity guard 101 is connected to voice hybrid network 111, dial tone detector 107, and power supply isolation resistor 106. When off-hook, DC power for RAM circuit 122 is supplied by capacitor 108 and resistor 106 via power supply .
control circuit 126 and main power 128. When on-hook, DC power for RAM circuit 122 is supplied by capacitor 104 and resistor 102 via power supply control circuit 126 and backup power 130.
Microcontroller 115 may be implemented using a generally available microprocessor of conventional design. A microprocessor should be selected that has a relatively low current drain, due to the fact that the microprocessor is to be powered from the tip/ring line 121, and not from a continuous power supply. The microcontroller 115 is coupled to RAM circuit 122. Although RAM circuit 122 and microcontroller 115 areshown as separate elements in the configuration of FIG. 1, RAM circuit 122 could be o combined with microcontroller 115 in the same integrated circuit package.
As previously stated, microcontroller 115 controls the operation of a DTMF tone generator 109. In response to microcontroller 115 comm~n~ signals, DTMF tone generator 109 produces DTMF tones which are coupled through voice hybrid network111 and polarity guard 101 to tip/ring line 121. Dial tone detector 107 detects the presence of dial tone on tip/ring line 121, and signals the microcontroller 115 as to the presence or absence of dial tone.
FIG. 2 is a flowchart describing the sequence of operations implemented by the system of FIG. 1 according to a first embodiment disclosed herein. The operational sequence of FIG. 2 is p~lrolllled when the system of FIG. 1 is to be employed inconjunction with a telephonic device that operates using a power source 113. Theprogram commences at block 301. At block 303, a test is pcl~,llled to ascertain whether or not the tip/ring line 121 (FIG. 1) and a power source 113 (FIG. 1) are both connected to the automatic dialing mode selection system 100 (FIG. 1). In this context, a tip/ring line 121 "connection" means that one end of the tip/ring line 121 is connected to the automatic dialing mode selection system 100 and the other end of the tip/ring line 121 is connected to an active communications port at the public switched telephone network (PSTN), with electrical coupling between the PSTN and the automatic dialing mode Io 2 1 867q4 selection system 100. Such a connection signifies that tip/ring line 121 has been activated and placed into service by the PSTN, and that no discontinllities or shorts exist between the PSTN and the automatic dialing mode selection system 100.
The PSTN applies a DC voltage potential of approximately 48 VDC across s activated tip/ring lines when all devices connected to that tip/ring line are on-hook and the tip/ring line is not receiving a ring signal from an incoming call. This DC voltage potential may be l1tili~1 to power the automatic dialing mode selection system 100 in a standby mode, so long as the current drain of this system is sufficiently low so as not to be interpreted as an off-hook condition by the PSTN. This requirement is easily achieved 10 through the use of CMOS semiconductor devices in automatic dialing mode selection system 100.
An ID bit is used to specify whether or not the dialing mode needs to be set. This ID bit could be stored, for example, in a memory register of the microcontroller, a memory device coupled to the microcontroller, a flip-flop, a latch circuit, or the like. For purposes of illustration, an ID bit value of "1" may be defined as specifying that the dialing mode has been set. If the dialing mode has been established, and the tip/ring line 121 remains connected to the automatic dialing mode selection system 100, the value of the ID bit remains set at 1. An ID bit value of "0" may be defined as specifying that the dialing mode needs to be set. Note that, if the tip/ring line 121 remains connected to the 20 automatic dialing mode selection system, the value of the ID bit is retained. If tip/ring line 121 does not remain connected to automatic dialing mode selection system 100, the value of the ID bit is reset to "0".
If either the power source 113 or the tip/ring line 121 are not connected to system 100, the negative branch from block 303 leads back to block 301 where the program waits 25 until both of the aforementioned connections are made. Likewise, if neither the power source 113 nor the tip/ring line 121 are connected to automatic dialing mode selection system 100, the program waits until both connections are made.
Program control progresses to block 305 where the microcontroller 115 (FIG. 1) activates the line switch 105 (FIG. 1) to place the system 100 into an off-hook condition.
After automatic dialing mode selection system 100 is placed into an off-hook condition at block 305, program control progresses to block 307 where the microcontroller 115 (FIG.
5 1) activates DTMF tone generator 109 (FIG. 1) to dial a DTMF digit. In a PBX
en~iro~ .ent, note that system 100 could be programmed to select the dialing mode of the PBX itself or, alternatively, system 100 could be programmed to select the dialing mode of the outgoing telephone line connecting the PBX to the PSTN. In the case where the dialing mode of the outgoing telephone line is to be determined, a DTMF digit of 9 is o dialed at block 307, followed by the dialing of a second DTMF digit. This ensures proper operation in a PBX environment where a DTMF digit of 9 causes the PBX to access an outgoing line to the PSTN. If a particular PBX system uses a digit or digits other than 9 to access the PSTN, then the DTMF tone generator 109 should dial such access digits.
Hereinafter, it will be assumed that the DTMF digit "9" is used to provide PSTN access from a PBX, it being understood that a digit or digits other than 9 could also be employed for this purpose.
After a DTMF digit is dialed (block 307), the dial tone detector 107 (FIG. 1) checks the tip/ring line 121 for the presence of dial tone (FIG. 2, block 309). If dial tone is present, program control jumps ahead to block 311, where the microcontroller 115 is 20 set to implement pulsed dial signaling. This function may be performed by setting a mode bit to a value signifying pulsed dial signaling. Such a mode bit could be stored, for example, in a memory register of the microcontroller, a memory device coupled to the microcontroller, a flip-flop, a latch circuit, or the like. For purposes of illustration, a mode bit value of "1" may be defined as specifying pulsed dial si~lin~, and a mode bit 25 value of "0" may be defined as specifying touch-tone dial si~ling If dial tone is absent at block 309, the program advances to block 315 where the microcontroller is set to implement touch-tone dial sign~ling by setting the mode bit to the a~r~liate value.
- ~ 12 2 1 86794 After block 311 or, alternatively, block 315, is pelro~ ed, program control passes to block 313, where the microcontroller sets the ID bit to indicate that the dial si~ling mode, i.e., the dialing mode, has been set. After the ID bit has been set, the microcontroller continlle~ to use the mode bit to determine the dialing mode that is to be 5 employed (block 316). From time to time, the microcontroller monitors the ID bit (block 317) to determine whether or not the tip/ring line 121 (FIG. 1) remains connected to the automatic dialing mode selection system 100 (FIG. 1). If the tip/ring line 121 remains connected to the automatic dialing mode selection system 100, the system retains the dial sign~lin~ mode previously determined at block 311 or block 315, and the program loops o back to block 316. If the tip/ring line 121 is disconnected from automatic dialing mode selection system 100, the ID bit is reset to "0", and the program loops back to block 303 and waits until the system is connected to power source 113 and tip/ring line 121.
In a PBX environment, prior to the time that PSTN access digits, such as a DTMF
"9", are dialed, no connection exists between the PSTN and the automatic dialing mode selection system 100. If the digit 9 (or other digits providing PSTN access) are dialed at block 307, an automatic dialing mode selection system 100 connected to an office PBX
forms a communications link with the PSTN after the dialing of the access digit(s), i.e., after the "9" is dialed. At this time, the PSTN will automatically apply a dial tone to the automatic dialing mode selection system 100 which replaces the dial tone generated by 20 the PBX. The automatic dialing mode selection system 100 now proceeds to select an appr~.;ate dialing mode using the same procedure as in the case where no PBX is employed. In this manner, the dialing mode selection is not based upon the "reappearance" of dial tone caused by the PBX connecting system 100 to the PSTN.Rather, dialing mode selection is properly based upon the dialing mode capabilities of the 25 tip/ring line between the PSTN and the PBX. This situation can be addressed by pro~.. ;.. g microcontroller 115 and/or by instructing the user to dial a DTMF "9"
followed by the entry of at least one additional DTM~ digit.
The scenario in the preceding paragraph addresses various problems presented by a PBX environment. However, this scenario is not intended to imply that the procedure of FIG. 2 is applicable only in a PBX environment. Note that the procedure of FIG. 2 is applicable to environments which do not include a PBX, as in the situation where a 5 telephonic device is connected to a tip/ring line providing a direct co"l~"ications link to the PSTN. In systems having such direct links, any DTMF digit (including 9) could be dialed at block 307.
It is possible to automatically change the dialing mode from pulse to touch-toneafter the last digit of a telephone number has been pulse-dialed. For exarnple, such a o technique is disclosed in U.S. Patent No. 5,369,697 which issued to Murray et al. on November 29, 1994. Although somewhat useful in situations where an interactive touch-tone service must be accessed from a telephone line equipped to receive only pulsed dialing signals, this approach presents some serious shortcomings. All outgoing calls are placed using pulse dialing and, after the call has been dialed, the dialing mode is changed to touch-tone signaling for the duration of the call. The mode is switched from pulse to touch-tone when the calling telephone receives ring back signals, DTMF signals, voice, or data.- This technique presents a shortcoming in that the actual dial sipn~lin~
capabilities of the tip-ring line are not determined. Rather, it is assumed that the telephonic device user is connected to a tip-ring line equipped to support pulsed dialing only. Although the technique allows access to on-line touchtone services, the telephone call is always established using relatively slow, inefficient pulse (li~ling.
In the embodiments of FIGS. 1 and 2, microcontroller 115 may be programmed such that, in response to user input (i.e., a predetermined DTMF key press sequence), the microcontroller will set the dialing mode bit from pulsed dialing to touch-tone dialing 2s after the call has been completed, but only for the duration of the call. In this manner, the user can access interactive touch-tone services from a tiptring line equipped to support only pulsed dial sign~ling for the purpose of completing an outgoing telephone call. Even though such pulsed telephone lines do not support touch-tone dial sign~lin~ for purposes of call establi~hment after the call has been established on such a line using pulsed sign~lin~, the line can be used to communicate DTMF signals among telephonic devices connected to the line.
FIG. 3 is flowchart describing a sequence of operations implemented by the automatic dialing mode selection system 100 of FIG. 1 according to a second embodiment disclosed herein. The sequence of operations described in connection with FIG. 3 are implemented in the operational environment of a conventional POTS
telephone. The program commences at block 401. At block 403, the POTS telephone is o connected to a tip/ring line 121 (FIG. 1). In this context, a tip/ring line 121 "connection"
means that one end of the tip/ring line 121 is connected to the automatic dialing mode selection system 100 and the other end of the tip/ring line 121 is connected to an active co",."~ ications port at the public switched telephone network (PSTN), with electrical coupling between the PSTN and the automatic dialing mode selection system 100.
The program advances to block 404. When the voltage on the first input terminal 151 of the power supply control circuit 126 rises above a pre~letçrrnined threshold, voltage sensing circuit 135 resets latch circuit 148 with an "ID bit" value of 0, signifying that the dialing mode has not yet been determined. The program then waits until the POTS user places the POTS telephone off-hook. At block 407, the POTS user places the 20 POTS telephone in an off-hook condition, and dials the telephone (i.e., enters digits) to place a call to any telephone number. After digits are entered at block 407, microcontroller 115 (FIG. 1) reads the ID bit to determine whether or not the dialing mode has already been set (block 408). If so, the program advances to block 430 where the microcontroller 115 reads the value of a mode bit stored in RAM circuit 122. The 25 value of the mode bit is set to specify either pulse dialing or touch-tone (li~ling For example, a mode bit value of 1 may correspond to touch-tone (li~ling, and a mode bit value of 0 may correspond to pulsed dialing. After block 430, the program advances to "~ -block 410, where the microcontroller 115 dials the telephone number previously entered by the user at block 407 using the dial signaling mode determined by the value of the mode bit. The program then jumps ahead to block 418.
The negative branch from block 408 leads to block 409, where the microcontrollers 115 activates the DTMF tone generator 109 (FIG. 1) to generate in DTMF mode the first digit entered by the POTS user at block 407 (FIG. 3). The program progresses to block 411, at which time the dial tone detector 107 (FIG. 1) checks the tip/ring line 121 for the presence of dial tone. If dial tone is present, the program advances to block 415 where microcontroller 115 (FIG. 1) loads RAM circuit 122 with a "mode bit" value specifying pulsed dialing for the POTS telephone, thereby setting the dialing mode to pulse. The program then advances to block 416 where the microcontroller 115 pulse dials the first digit of the telephone number previously entered by the user at block 407, and the program progresses to block 417. If dial tone is not present at block 411, the program advances to block 413 where microcontroller 115 (FIG. 1) loads RAM circuit 122 with a "mode bit" value specifying touch-tone (DTMF) dialing for the POTS telephone, thereby setting the dial si~ling mode to touch-tone. As stated above, this "mode bit" is stored as a one-bit value in RAM circuit 122.
After block 413 is performed, program control progresses to block 417. Program control also progresses to block 417 from block 416. At block 417, the microcontroller 115 sets the "ID bit" to a value of 1, to signify that the dialing mode has been set. This "ID bit" is stored as a one-bit value in latch 148. At block 418, the microcontroller 115 contimles to dial the telephone number previously entered by the user at block 407. This number is dialed using the a~l~liate dial sign~ling mode as specified by the mode bit.
The microcontroller 115 continues to use the mode bit to determine pulse or touch-tone dial si~ ng mode (block 419) for any numbers entered by the user. The microcontroller 115 then monitors the ID bit at the output of latch 148 (block 420). If the voltage on the first input terminal 151 of the power supply control circuit 126 falls below ~ 16 a pre~eterrnined threshold, voltage sense circuit 135 resets the latch 148, signifying that the POTS telephone has been removed from the tip/ring line 121, and/or that tip/ring line 121 is no longer active. If the latch has been reset, execution of the program is suspended (block 420) until the voltage on the first input terminal 151 once again exceeds a 5 pre~letPrmined threshold, whereupon the program then loops back to block 403. If the latch has not been reset, the program loops back to block 419.
5 2. nes~ lionofPriorArt The dialing mode of telephonic devices must be set to specify the a~propliate dialing mode, such as pulsed dialing or touch-tone dialing. State-of-the-art telephonic devices do not include any means by which the capabilities of a given tip-ring connection may be automatically checked to determine the a~pi~liate dialing mode. Although 10 many tip-ring lines connected to the Public Switched Telephone Network are equipped to accept touch-tone dialing signals, other tip-ring lines will only accept pulsed dialing signals. The device user must m~ml~lly select an app,~liate dialing mode by setting a slide switch to a first position corresponding to touch-tone ~ lin~, or to a second position corresponding to pulsed ~ ling Telephonic device users are required to know the dial sign~lin~ capabilities of a given tip-ring line in order to select the proper dialing mode. Of~elltimes~ the dialing mode is not known, and, as a result, the slide switch is not set to the proper position. If the switch is set to pulsed dialing when the tip-ring line is equipped to implement touch-tone sign~ling, the device user will not benefit from the ~ltili7~tion of touch-tone 20 si~n~lin~- The telephonic device will take a long time to place an outgoing call relative to other telephonic equipment that the user may have employed in the past. If the user ~llelll~ to access services that utilize end-to-end touch tone sign~ling, such services will be rendered inoperative. On the other hand, if the switch is set to touch-tone dialing when the tip-ring line is only equipped to implement pulsed di~ling, the device user will not be 25 able to originate any outgoing telephone calls. When the dialing mode slide switch is not set to the proper position, the user may return the device to the seller because the device is perceived as having relatively poor p~_lrol.llance.
2 21 867~4 What is needed is a technique for automatically detc~ the dialing mode capabilities of a tip-ring line, and for automatically setting the dialing mode of a telephonic device to specify the appr~1iate dialing mode. Such mode setting should take place when the telephonic device is first connected to the tip-ring line, and the mode setting should remain in force until the telephonic device is removed from that tip-ring line. However, an option may be provided for the user to specify mode setting for the duration of a telephone call after the call has been established by the PSTN (public switched telephone network), thereby permitting the user to access interactive touch-tone services from a tip/ring line equipped to implement only pulsed dial si~n~lin~ for o purposes of call establishment.
y of ~he ~r vention Automatic dialing mode selection techniques are ut~ e~l in the operational environment of a telephonic device connected to a tip-ring line. The telephonic device includes dialing mode assessment ch~ y and dialing mode setting cil'cuilly. The dialing mode ~sessment circuitry automatically determines the dialing mode supported by the tip-ring line. The dialing mode setting circuill ~ is responsive to the dialing mode assessment circuilly for automatically setting the dialing mode of the telephonic device to specify the dialing mode supported by the tip-ring line, such as pulsed dialing or touch-tone lli?ling. The dialing mode is automatically set at the time that the telephonic device is first connected to the tip-ring line, and the telephonic device retains that mode setting until the device is removed from the tip-ring line.
Brief l)escriptior of the l)rawin~
FIG. 1 is a har.lw~e block diagram setting forth an illustrative embodiment of the automatic dialing mode selection system disclosed herein;
FIG. 2 is a flowchart describing a first sequence of operations implemented by the system of FIG. l; and FIG. 3 is a flowchart describing a second sequence of operations implemented by the system of FIG. 1.
l)etailed ~escription of the Preferred Embodiments FIG. 1 is a hardw~e block diagram setting forth an illustrative embodiment of the automatic dialing mode selection system 100 disclosed herein. Automatic dialing mode selection system 100 may be used in conjunction with, and/or incorporated into, virtually any telephonic device that is equipped to interface with a tip/ring line 121. A polarity guard 101 circuit is connected across tip/ring line 121. Polarity guard circuit 101 includes four semiconductor diodes in a bridge rectifier arrangement, and enables the automatic dialing mode selection system 100 to function properly, independent of the actual polarity of the DC voltages on tip/ring line 121. Polarity guard circuit 101 is coupled to a line switch 105, which may be an electronic, electromechanical, or mechanical line switch of conventional design. An optional mechanical hook switch 103 is present if, for example, the telephonic device consists of a POTS telephone (plain old telephone set). This mechanical hook switch 103 is coupled to line switch 105.
A first energy storage device is employed to store electrical power while the automatic dialing mode selection system 100 is in an on-hook state with respect to tip/ring line 121. In the present example, this energy storage device consists of an electrolytic capacitor 104 which is charged through an isolation resistor 102. Electrolytic capacitor 104 is selected to have a relatively high capacitance value of, for example, 1000 microfarads or greater, and as low a value of leakage current as is practicable. The DC
potential across capacitor 104 is coupled to a first input tçrmin~l 151 of a power supply control circuit 126. The DC potential across capacitor 104 is also coupled to a first input tçrmin~l of a second voltage sense circuit 135.
A second energy storage device is employed to store electrical power while the automatic dialing mode selection system 100 is in an off-hook state with respect to tip/ring line 121. In the example of FIG. 1, this second energy storage device consists of ~ ~ 21 ~6794 an electrolytic capacitor 108 which is charged through an isolation resistor 106. An ind~lctor having a relatively high impedance at audio frequencies may optionally be placed in series with isolation resistor 106 (or, alternatively, used in place of isolation resistor 106) to minimi7e the extent to which the combination of eleçtrolytic capacitor 108 and isolation resistor 106 ~ttenl-~te the audio frequency range. Electrolytic capacitor 108 is selected to have a relatively high capacitance value of, for example, 1000 microfarads or greater, and as low a value of leakage current as is practicable. A
rechargeable battery could be used in place of electrolytic capacitor 108 if desired. The DC potential across capacitor 108 is coupled to a second input tPrmin~l 153 of power o supply control circuit 126.
An optional power source 113 is coupled to a third input termin~l 155 of power supply control circuit 126. This power source 113 may comprise, for example, an AC
adapter that converts conventional residential AC current into a low-voltage DC current.
Such AC adapters typically include a power transformer that steps down this AC voltage (nominally 117 volts AC or 220 volts AC, depending on location) to a lower voltage level (e.g., 6.3 or 12.6 volts AC). The stepped-down AC voltage is applied to a diode bridge rectifier and the rectified DC voltage is filtered by means of an electrolytic capacitor.
Alternatively, power source 113 may comprise a rechargeable battery, a non-rechargeable battery, and/or a rechargeable battery combined with an AC adapter and battery-charging Cil~;uill~.
Power supply control circuit 126 selectively applies DC power to a main power 128 output t~rmin~l and/or a backup power terminal 130 based upon the presence or absence of DC power at each of the input termin~l~ 151, 153, 155 of the power supply control circuit. For example, if power is present at all ofthe input termin~l~ 151, 153, and 155, then power supply control circuit 126 applies DC power to both the main power 128 output and the backup power 130 output. However, if power is present at first input terminal 151, but no power is present at second and third input termin~l~ 153, 155, respectively, then power supply control circuit 126 only applies powér to the backup power 130 output and not to the main power 128 output. The backup power output 130 of the power supply control circuit 126 is coupled to a second input of the second voltage sense circuit 135. In practice, various combinations of transistors, diodes, other semiconductor devices, and/or logic gates may be employed to implement power supply control circuit 126. The construction of a suitable circuit for power supply control circuit 126 is a matter within the knowledge of those skilled in the art.
An electronic line switch may be employed for line switch 105 or, ~Itern~tively,line switch 105 may be a mechanical line switch. In the example of FIG. 1, line switch o 105 is coupled to an optional mechanical hook switch 103. Conventional components may be used to fabricate line switch 105 and mechanical hook switch 103. Line switch 105 is provided with a first port, a second port, and a control port for selectively enabling and disabling a commlmications pathway between the first and second ports. Polarity guard circuit 101 is coupled to the first port of line switch 105, and the control port of line switch 105 is coupled to microcontroller 115. The second port of line switch 105 is coupled to a voice hybrid network 111, and this second port is also coupled to a dial tone detector 107. The output from a DTMF tone generator 109 is coupled to voice hybrid network 111. The operation of DTMF tone generator 109 is controlled by microcontroller 115.
Voice hybrid network 111, DTMF tone generator 109, and dial tone detector 107 are components of conventional design, the details of which are generally known to those skilled in the art. For example, dial tone detector 107 may include an energy detector for detecting the presence of dial tone on tip/ring line 121. Dial tone detector 107 is coupled to microcontroller 115, and sends microcontroller 115 a signal indicative of whether or not dial tone exists.
A first voltage sense circuit 125 senses voltage on main power terminal 128, andthe second voltage sense circuit 135 senses voltage on voltage storage device 104. The 6 21 ~6794 first voltage sense circuit 125 is coupled to a first pulse generator 132. Upon sensing a voltage level above a predetçrrnined threshold, the first voltage sense circuit 125 activates the first pulse generator 132 to apply a pulse to the RESET termin~l of microcontroller 115. The first pulse generator 132 is powered from main power tetrnin~l 128. In this s manner, the combination of first voltage sense circuit 125 and first pulse generator 132 function as a power-on-reset circuit element that is responsive to voltage on main power termin~l 128 to reset microcontroller 115.
Microcontroller 115 may be implemented by a conventional microprocessor of a type well-known to those skilled in the art, and is coupled to an associated random-access o memory (RAM) circuit 122. Microcontroller 115 uses RAM 122 to store a mode control bit that indicates whether tone or dial pulse sign~lin~ is to be used. RAM 122 is coupled to main power 128 as well as backup power 130.
The operation of line switch 105 is controlled and monitored by a microcontroller 115. As previously stated, microcontroller 115 also controls the operation of DTMF tone generator 109. DTMF tone generator 109 is employed for the purpose of dete- .. i~ the dial sign~ling capabilities of tip/ring line 121, as will be described in greater detail hereinafter. The DTMF tone generator 109 is also used to place outgoing telephone calls and to access on-line interactive services that use DTMF si~lin~;.
The output of second voltage sense circuit 135 is coupled to a second pulse generator 143. When activated by the voltage sense circuit 135, which occurs when voltage sense circuit 135 senses a voltage above or below a predeterrnined threshold, the second pulse generator 143 applies a pulse to a reset input of latch 148. Latch 148 may be implemented using a conventional latch device. A set input of latch 148 is coupled to microcontroller 115. The output of latch 148 is concept~l~li7çd as l~resentin~ an "ID
bit". The value of this ID bit is forwarded to microcontroller 115 to indicate the time at which the sequence to set the dialing mode must be pe.ro~ ed.
7 21867~4 Microcontroller 115 may be coupled to an optional display device for providing an indication as to the dialing mode capabilities of tip/ring line 121, an indication as to the operations presently being pc.rolllled by automatic dialing mode selection system 100, and/or user plo.ll~ so as to enable a proper determin~tion of dialing mode at the proper s time, as when the telephonic device is connected to a new tip/ring line.
The embodiment of FIG. 1 is used in conjunction with telephonic devices that arebattery-powered, and/or powered from a conventional AC (~Itern~ting current) wall outlet. Such telephonic devices include telephone answering m~cllines, cordless telephones, fax machines, many present-day electronic telephones with enhanced fealules that require a steady source of power, as well as other types of equipment that may be connected to a tip/ring line. The embodiment of FIG. 1 also operates in conjunction with plain, old telephone devices, also known as "POTS" telephones, which do not generally include power source 113. If it is desired to equip a POTS telephone with enhanced features requiring the use of active semiconductor devices, these devices must thc.cfolc be powered up using energy extracted from tip/ring line 121.
In the case where automatic dialing mode selection system 100 is employed in theoperational environment of a POTS telephone that does not include a power supply, the system opc.ates as follows. Tip/ring line 121 is connected to a polarity guard circuit 101 which, in the present example, includes four diodes arranged in a conventional bridge rectifier configuration. While a POTS telephone is on-hook, in most cases, insufficient power exists to operate microcontroller 115. However, the bridge rectifier of polarity guard circuit 101 delivers a DC voltage of a given polarity to capacitor 104, independent of the actual polarity of the DC voltages on tip/ring line 121. These DC voltages may be used to trickle-charge an energy storage device, which, in the present example, consists of electrolytic capacitor 104 which is charged through isolation resistor 102. Electrolytic capacitor 104 is selected to have a relatively high capacitance value of, for example, 1,000 microfarads or greater, and as low a value of leakage current as is practicable.
An inductQr having a relatively high impedance at audio frequencies may optionally be placed in series with isolation resistor 102 to minimi~e the extent to which the combination of capacitor 104 and resistor 102 attenuate the audio frequency range.
The DC potential across capacitor 104 is used to power DC power supply control circuit 126 and latch circuit 148. The DC potential across capacitor 104 may also be used to power RAM 122 when RAM 122 is in a standby mode. In standby mode, RAM 122 retains the contents of its memory, but devices external to RAM 122 are not able to read the contents of RAM 122, nor are such external devices able to write to RAM 122.First voltage sense circuit 125 detects the presence of tip/ring voltage at the output of polarity guard 101. This voltage sensing circuit may include, for example, a Zener diode and/or a comparator device.
When the POTS telephone is off-hook, sufficient power exists on tip/ring line 121 to power microcontroller 115 and RAM circuit 122 using a power supply circuit con~i~ting of an isolation resistor 106 and a capacitor 108. An induGtor having relatively high impedance at audio frequencies may optionally be placed in series with isolation resistor 106 to minimi7e the extent to which the combination of resistor 106 and capacitor 108 attenuate the audio frequency range. Microcontroller 115 includes a DC powersupply input which is connected to main power 128. Upon the occurrence of an off-hook condition, power supply control circuit 126 couples this DC power supply input to capacitor 108 through a current limiting resistor 106. In the case of a POTS telephone, line switch 105 may, in fact, represent a mechanical switch hook. Altern~tively, the mechanical switch hook 103 of a conventional POTS telephone may be coupled to line switch 105, as shown in FIG. 1. The POTS telephone is placed in the off-hook condition by operation of mechanical switch hook 103 andtor line switch 105. In the off-hook condition, the output of polarity guard 101 is connected to voice hybrid network 111, dial tone detector 107, and power supply isolation resistor 106. When off-hook, DC power for RAM circuit 122 is supplied by capacitor 108 and resistor 106 via power supply .
control circuit 126 and main power 128. When on-hook, DC power for RAM circuit 122 is supplied by capacitor 104 and resistor 102 via power supply control circuit 126 and backup power 130.
Microcontroller 115 may be implemented using a generally available microprocessor of conventional design. A microprocessor should be selected that has a relatively low current drain, due to the fact that the microprocessor is to be powered from the tip/ring line 121, and not from a continuous power supply. The microcontroller 115 is coupled to RAM circuit 122. Although RAM circuit 122 and microcontroller 115 areshown as separate elements in the configuration of FIG. 1, RAM circuit 122 could be o combined with microcontroller 115 in the same integrated circuit package.
As previously stated, microcontroller 115 controls the operation of a DTMF tone generator 109. In response to microcontroller 115 comm~n~ signals, DTMF tone generator 109 produces DTMF tones which are coupled through voice hybrid network111 and polarity guard 101 to tip/ring line 121. Dial tone detector 107 detects the presence of dial tone on tip/ring line 121, and signals the microcontroller 115 as to the presence or absence of dial tone.
FIG. 2 is a flowchart describing the sequence of operations implemented by the system of FIG. 1 according to a first embodiment disclosed herein. The operational sequence of FIG. 2 is p~lrolllled when the system of FIG. 1 is to be employed inconjunction with a telephonic device that operates using a power source 113. Theprogram commences at block 301. At block 303, a test is pcl~,llled to ascertain whether or not the tip/ring line 121 (FIG. 1) and a power source 113 (FIG. 1) are both connected to the automatic dialing mode selection system 100 (FIG. 1). In this context, a tip/ring line 121 "connection" means that one end of the tip/ring line 121 is connected to the automatic dialing mode selection system 100 and the other end of the tip/ring line 121 is connected to an active communications port at the public switched telephone network (PSTN), with electrical coupling between the PSTN and the automatic dialing mode Io 2 1 867q4 selection system 100. Such a connection signifies that tip/ring line 121 has been activated and placed into service by the PSTN, and that no discontinllities or shorts exist between the PSTN and the automatic dialing mode selection system 100.
The PSTN applies a DC voltage potential of approximately 48 VDC across s activated tip/ring lines when all devices connected to that tip/ring line are on-hook and the tip/ring line is not receiving a ring signal from an incoming call. This DC voltage potential may be l1tili~1 to power the automatic dialing mode selection system 100 in a standby mode, so long as the current drain of this system is sufficiently low so as not to be interpreted as an off-hook condition by the PSTN. This requirement is easily achieved 10 through the use of CMOS semiconductor devices in automatic dialing mode selection system 100.
An ID bit is used to specify whether or not the dialing mode needs to be set. This ID bit could be stored, for example, in a memory register of the microcontroller, a memory device coupled to the microcontroller, a flip-flop, a latch circuit, or the like. For purposes of illustration, an ID bit value of "1" may be defined as specifying that the dialing mode has been set. If the dialing mode has been established, and the tip/ring line 121 remains connected to the automatic dialing mode selection system 100, the value of the ID bit remains set at 1. An ID bit value of "0" may be defined as specifying that the dialing mode needs to be set. Note that, if the tip/ring line 121 remains connected to the 20 automatic dialing mode selection system, the value of the ID bit is retained. If tip/ring line 121 does not remain connected to automatic dialing mode selection system 100, the value of the ID bit is reset to "0".
If either the power source 113 or the tip/ring line 121 are not connected to system 100, the negative branch from block 303 leads back to block 301 where the program waits 25 until both of the aforementioned connections are made. Likewise, if neither the power source 113 nor the tip/ring line 121 are connected to automatic dialing mode selection system 100, the program waits until both connections are made.
Program control progresses to block 305 where the microcontroller 115 (FIG. 1) activates the line switch 105 (FIG. 1) to place the system 100 into an off-hook condition.
After automatic dialing mode selection system 100 is placed into an off-hook condition at block 305, program control progresses to block 307 where the microcontroller 115 (FIG.
5 1) activates DTMF tone generator 109 (FIG. 1) to dial a DTMF digit. In a PBX
en~iro~ .ent, note that system 100 could be programmed to select the dialing mode of the PBX itself or, alternatively, system 100 could be programmed to select the dialing mode of the outgoing telephone line connecting the PBX to the PSTN. In the case where the dialing mode of the outgoing telephone line is to be determined, a DTMF digit of 9 is o dialed at block 307, followed by the dialing of a second DTMF digit. This ensures proper operation in a PBX environment where a DTMF digit of 9 causes the PBX to access an outgoing line to the PSTN. If a particular PBX system uses a digit or digits other than 9 to access the PSTN, then the DTMF tone generator 109 should dial such access digits.
Hereinafter, it will be assumed that the DTMF digit "9" is used to provide PSTN access from a PBX, it being understood that a digit or digits other than 9 could also be employed for this purpose.
After a DTMF digit is dialed (block 307), the dial tone detector 107 (FIG. 1) checks the tip/ring line 121 for the presence of dial tone (FIG. 2, block 309). If dial tone is present, program control jumps ahead to block 311, where the microcontroller 115 is 20 set to implement pulsed dial signaling. This function may be performed by setting a mode bit to a value signifying pulsed dial signaling. Such a mode bit could be stored, for example, in a memory register of the microcontroller, a memory device coupled to the microcontroller, a flip-flop, a latch circuit, or the like. For purposes of illustration, a mode bit value of "1" may be defined as specifying pulsed dial si~lin~, and a mode bit 25 value of "0" may be defined as specifying touch-tone dial si~ling If dial tone is absent at block 309, the program advances to block 315 where the microcontroller is set to implement touch-tone dial sign~ling by setting the mode bit to the a~r~liate value.
- ~ 12 2 1 86794 After block 311 or, alternatively, block 315, is pelro~ ed, program control passes to block 313, where the microcontroller sets the ID bit to indicate that the dial si~ling mode, i.e., the dialing mode, has been set. After the ID bit has been set, the microcontroller continlle~ to use the mode bit to determine the dialing mode that is to be 5 employed (block 316). From time to time, the microcontroller monitors the ID bit (block 317) to determine whether or not the tip/ring line 121 (FIG. 1) remains connected to the automatic dialing mode selection system 100 (FIG. 1). If the tip/ring line 121 remains connected to the automatic dialing mode selection system 100, the system retains the dial sign~lin~ mode previously determined at block 311 or block 315, and the program loops o back to block 316. If the tip/ring line 121 is disconnected from automatic dialing mode selection system 100, the ID bit is reset to "0", and the program loops back to block 303 and waits until the system is connected to power source 113 and tip/ring line 121.
In a PBX environment, prior to the time that PSTN access digits, such as a DTMF
"9", are dialed, no connection exists between the PSTN and the automatic dialing mode selection system 100. If the digit 9 (or other digits providing PSTN access) are dialed at block 307, an automatic dialing mode selection system 100 connected to an office PBX
forms a communications link with the PSTN after the dialing of the access digit(s), i.e., after the "9" is dialed. At this time, the PSTN will automatically apply a dial tone to the automatic dialing mode selection system 100 which replaces the dial tone generated by 20 the PBX. The automatic dialing mode selection system 100 now proceeds to select an appr~.;ate dialing mode using the same procedure as in the case where no PBX is employed. In this manner, the dialing mode selection is not based upon the "reappearance" of dial tone caused by the PBX connecting system 100 to the PSTN.Rather, dialing mode selection is properly based upon the dialing mode capabilities of the 25 tip/ring line between the PSTN and the PBX. This situation can be addressed by pro~.. ;.. g microcontroller 115 and/or by instructing the user to dial a DTMF "9"
followed by the entry of at least one additional DTM~ digit.
The scenario in the preceding paragraph addresses various problems presented by a PBX environment. However, this scenario is not intended to imply that the procedure of FIG. 2 is applicable only in a PBX environment. Note that the procedure of FIG. 2 is applicable to environments which do not include a PBX, as in the situation where a 5 telephonic device is connected to a tip/ring line providing a direct co"l~"ications link to the PSTN. In systems having such direct links, any DTMF digit (including 9) could be dialed at block 307.
It is possible to automatically change the dialing mode from pulse to touch-toneafter the last digit of a telephone number has been pulse-dialed. For exarnple, such a o technique is disclosed in U.S. Patent No. 5,369,697 which issued to Murray et al. on November 29, 1994. Although somewhat useful in situations where an interactive touch-tone service must be accessed from a telephone line equipped to receive only pulsed dialing signals, this approach presents some serious shortcomings. All outgoing calls are placed using pulse dialing and, after the call has been dialed, the dialing mode is changed to touch-tone signaling for the duration of the call. The mode is switched from pulse to touch-tone when the calling telephone receives ring back signals, DTMF signals, voice, or data.- This technique presents a shortcoming in that the actual dial sipn~lin~
capabilities of the tip-ring line are not determined. Rather, it is assumed that the telephonic device user is connected to a tip-ring line equipped to support pulsed dialing only. Although the technique allows access to on-line touchtone services, the telephone call is always established using relatively slow, inefficient pulse (li~ling.
In the embodiments of FIGS. 1 and 2, microcontroller 115 may be programmed such that, in response to user input (i.e., a predetermined DTMF key press sequence), the microcontroller will set the dialing mode bit from pulsed dialing to touch-tone dialing 2s after the call has been completed, but only for the duration of the call. In this manner, the user can access interactive touch-tone services from a tiptring line equipped to support only pulsed dial sign~ling for the purpose of completing an outgoing telephone call. Even though such pulsed telephone lines do not support touch-tone dial sign~lin~ for purposes of call establi~hment after the call has been established on such a line using pulsed sign~lin~, the line can be used to communicate DTMF signals among telephonic devices connected to the line.
FIG. 3 is flowchart describing a sequence of operations implemented by the automatic dialing mode selection system 100 of FIG. 1 according to a second embodiment disclosed herein. The sequence of operations described in connection with FIG. 3 are implemented in the operational environment of a conventional POTS
telephone. The program commences at block 401. At block 403, the POTS telephone is o connected to a tip/ring line 121 (FIG. 1). In this context, a tip/ring line 121 "connection"
means that one end of the tip/ring line 121 is connected to the automatic dialing mode selection system 100 and the other end of the tip/ring line 121 is connected to an active co",."~ ications port at the public switched telephone network (PSTN), with electrical coupling between the PSTN and the automatic dialing mode selection system 100.
The program advances to block 404. When the voltage on the first input terminal 151 of the power supply control circuit 126 rises above a pre~letçrrnined threshold, voltage sensing circuit 135 resets latch circuit 148 with an "ID bit" value of 0, signifying that the dialing mode has not yet been determined. The program then waits until the POTS user places the POTS telephone off-hook. At block 407, the POTS user places the 20 POTS telephone in an off-hook condition, and dials the telephone (i.e., enters digits) to place a call to any telephone number. After digits are entered at block 407, microcontroller 115 (FIG. 1) reads the ID bit to determine whether or not the dialing mode has already been set (block 408). If so, the program advances to block 430 where the microcontroller 115 reads the value of a mode bit stored in RAM circuit 122. The 25 value of the mode bit is set to specify either pulse dialing or touch-tone (li~ling For example, a mode bit value of 1 may correspond to touch-tone (li~ling, and a mode bit value of 0 may correspond to pulsed dialing. After block 430, the program advances to "~ -block 410, where the microcontroller 115 dials the telephone number previously entered by the user at block 407 using the dial signaling mode determined by the value of the mode bit. The program then jumps ahead to block 418.
The negative branch from block 408 leads to block 409, where the microcontrollers 115 activates the DTMF tone generator 109 (FIG. 1) to generate in DTMF mode the first digit entered by the POTS user at block 407 (FIG. 3). The program progresses to block 411, at which time the dial tone detector 107 (FIG. 1) checks the tip/ring line 121 for the presence of dial tone. If dial tone is present, the program advances to block 415 where microcontroller 115 (FIG. 1) loads RAM circuit 122 with a "mode bit" value specifying pulsed dialing for the POTS telephone, thereby setting the dialing mode to pulse. The program then advances to block 416 where the microcontroller 115 pulse dials the first digit of the telephone number previously entered by the user at block 407, and the program progresses to block 417. If dial tone is not present at block 411, the program advances to block 413 where microcontroller 115 (FIG. 1) loads RAM circuit 122 with a "mode bit" value specifying touch-tone (DTMF) dialing for the POTS telephone, thereby setting the dial si~ling mode to touch-tone. As stated above, this "mode bit" is stored as a one-bit value in RAM circuit 122.
After block 413 is performed, program control progresses to block 417. Program control also progresses to block 417 from block 416. At block 417, the microcontroller 115 sets the "ID bit" to a value of 1, to signify that the dialing mode has been set. This "ID bit" is stored as a one-bit value in latch 148. At block 418, the microcontroller 115 contimles to dial the telephone number previously entered by the user at block 407. This number is dialed using the a~l~liate dial sign~ling mode as specified by the mode bit.
The microcontroller 115 continues to use the mode bit to determine pulse or touch-tone dial si~ ng mode (block 419) for any numbers entered by the user. The microcontroller 115 then monitors the ID bit at the output of latch 148 (block 420). If the voltage on the first input terminal 151 of the power supply control circuit 126 falls below ~ 16 a pre~eterrnined threshold, voltage sense circuit 135 resets the latch 148, signifying that the POTS telephone has been removed from the tip/ring line 121, and/or that tip/ring line 121 is no longer active. If the latch has been reset, execution of the program is suspended (block 420) until the voltage on the first input terminal 151 once again exceeds a 5 pre~letPrmined threshold, whereupon the program then loops back to block 403. If the latch has not been reset, the program loops back to block 419.
Claims (29)
1. An automatic dialing mode selection system for use with a telephonic device and a tip/ring line adapted for communications using at least one of a touch tone dialing mode and a pulsed dialing mode, the telephone line connected to a public switched telephone network (PSTN), the automatic dialing mode selection system comprising:
a dialing mode detector for determining a dialing mode for which the tip/ring line is adapted; and a dialing mode setting device, responsive to the dialing mode detector, for setting the dialing mode of the telephonic device to specify the dialing mode for which the tip-ring line is adapted.
a dialing mode detector for determining a dialing mode for which the tip/ring line is adapted; and a dialing mode setting device, responsive to the dialing mode detector, for setting the dialing mode of the telephonic device to specify the dialing mode for which the tip-ring line is adapted.
2. A telephonic device for use with a tip/ring line adapted for communications using at least one of a touch tone dialing mode and a pulsed dialing mode, the telephonic device comprising:
a dialing mode detector that determines a dialing mode for which the tip/ring line is adapted; and a dialing mode setting device, responsive to the dialing mode detector, for setting the dialing mode of the telephonic device to specify the dialing mode for which the tip-ring line is adapted.
a dialing mode detector that determines a dialing mode for which the tip/ring line is adapted; and a dialing mode setting device, responsive to the dialing mode detector, for setting the dialing mode of the telephonic device to specify the dialing mode for which the tip-ring line is adapted.
3. The automatic dialing mode selection system of Claim 1 wherein the dialing mode detector is activated upon connection of the telephonic device to the tip/ring line, and the dialing mode setting device continues to specify the dialing mode for which the tip/ring line is adapted until the telephonic device is removed from the tip/ring line.
4. The telephonic device of Claim 2 wherein the dialing mode detector is activated upon connection of the telephonic device to the tip/ring line, and the dialing mode setting device continues to specify the dialing mode for which the tip/ring line is adapted until the telephonic device is removed from the tip/ring line.
5. An automatic dialing mode selection method for use with a telephonic device connected to a tip-ring line, the telephonic device including dialing mode assessment circuitry and dialing mode setting circuitry, the method including the following steps:
(a) the dialing mode assessment circuitry automatically determining the dialing mode supported by the tip-ring line, wherein the dialing mode includes at least one of pulsed dialing and touch-tone dialing;
(b) the dialing mode setting circuitry, in response to the dialing mode assessment circuitry, setting the dialing mode of the telephonic device to specify the dialing mode supported by the tip-ring line.
(a) the dialing mode assessment circuitry automatically determining the dialing mode supported by the tip-ring line, wherein the dialing mode includes at least one of pulsed dialing and touch-tone dialing;
(b) the dialing mode setting circuitry, in response to the dialing mode assessment circuitry, setting the dialing mode of the telephonic device to specify the dialing mode supported by the tip-ring line.
6. An automatic dialing mode selection method as set forth in Claim 5 wherein the step of setting the dialing mode is performed at the time that the telephonic device is first connected to the tip-ring line, and the dialing mode remains so set until such time as the telephonic device is removed from the tip-ring line.
7. An automatic dialing mode selection method for use with a telephonic device having a processor, a power supply input port adapted for coupling to a power supply, a tip/ring port adapted for coupling to a tip/ring line, a dual-tone, multi-frequency (DTMF) tone generator coupled to the tip/ring port for generating DTMF tones, a dial tone detector for detecting the presence of dial tone, a dial pulse signal generator, an electronic switch coupled to the tip/ring port, and memory that stores a dialing mode bit specifying either a pulsed dialing mode to be implemented by the dial pulse signal generator or a touch-tone dialing mode to be implemented by the DTMF tone generator;
the method including the following steps:
(a) the processor checks for the existence of the both of the following conditions:
(i) the tip/ring line being coupled to the tip/ring port, and (ii) the power supply being coupled to the power supply input port;
(b) upon first detecting that (i) a tip/ring line is connected to the tip/ring port, and (ii) a power supply is coupled to the power supply input port, the processor activates the electronic switch to place the telephonic device in an off-hook condition with respect to the tip/ring line;
(c) the tone generator generates a DTMF digit;
(d) the dial tone detector monitors the tip/ring line for the presence of dial tone;
(e) upon detection of dial tone at step (d), the processor sets the dialing mode bit to specify the pulsed dialing mode; or, upon no detection of dial tone at step (d), the processor sets the dialing mode bit to specify the touch-tone dialing mode.
the method including the following steps:
(a) the processor checks for the existence of the both of the following conditions:
(i) the tip/ring line being coupled to the tip/ring port, and (ii) the power supply being coupled to the power supply input port;
(b) upon first detecting that (i) a tip/ring line is connected to the tip/ring port, and (ii) a power supply is coupled to the power supply input port, the processor activates the electronic switch to place the telephonic device in an off-hook condition with respect to the tip/ring line;
(c) the tone generator generates a DTMF digit;
(d) the dial tone detector monitors the tip/ring line for the presence of dial tone;
(e) upon detection of dial tone at step (d), the processor sets the dialing mode bit to specify the pulsed dialing mode; or, upon no detection of dial tone at step (d), the processor sets the dialing mode bit to specify the touch-tone dialing mode.
8. An automatic dialing mode selection method as set forth in Claim 7 wherein, after the performance of step (e), the existence of the tip/ring line being coupled to the tip/ring port is periodically monitored and, when the tip/ring line is not coupled to the tip/ring port, performing steps (a)-(e).
9. An automatic dialing mode selection system comprising a processor, a tip/ringport adapted for coupling to a tip/ring line, a tone generator coupled to the tip/ring port for generating DTMF tones, a dial tone detector for detecting the presence of dial tone, a dial pulse signal generator, an electronic switch coupled to the tip/ring port, a power supply input port equipped to accept an input voltage, and a memory for storing a dialing mode bit specifying either a pulsed dialing mode to be implemented by the dial pulse signal generator or a touch-tone dialing mode to be implemented by the tone generator.
and wherein the processor is coupled to the tip/ring port and the power supply input port; the processor further comprising means for determining whether or not (i) the tip/ring line is coupled to the tip/ring port, and (ii) an input voltage is coupled to the power supply input port;
and wherein the electronic switch is coupled to the processor, the electronic switch responding to the processor such that, upon the processor first detecting that a tip/ring line is coupled to the tip/ring port at the same time that a power supply is coupled to the power supply input port, the processor activating the electronic switch to place the automatic dialing mode selection system in an off-hook condition with respect to the tip/ring line.
and wherein the processor is coupled to the tip/ring port and the power supply input port; the processor further comprising means for determining whether or not (i) the tip/ring line is coupled to the tip/ring port, and (ii) an input voltage is coupled to the power supply input port;
and wherein the electronic switch is coupled to the processor, the electronic switch responding to the processor such that, upon the processor first detecting that a tip/ring line is coupled to the tip/ring port at the same time that a power supply is coupled to the power supply input port, the processor activating the electronic switch to place the automatic dialing mode selection system in an off-hook condition with respect to the tip/ring line.
10. An automatic dialing mode selection system as set forth in Claim 9 wherein the processor causes the tone generator to generate a dual-tone, multi-frequency (DTMF) digit in response to the electronic switch placing the automatic dialing mode selection system in an off-hook condition.
11. An automatic dialing mode selection system as set forth in Claim 10 wherein the dial tone detector is responsive to the presence of dial tone on the tip/ring line such that, upon detection of dial tone, the processor sets the dialing mode bit to specify the pulsed dialing mode.
12. An automatic dialing mode selection system as set forth in Claim 10 wherein the dial tone detector is responsive to the absence of dial tone on the tip/ring line such that, upon no detection of dial tone, the processor sets the dialing mode bit to specify the touch-tone dialing mode.
13. An automatic dialing mode selection system as set forth in Claim 11 wherein the processor includes means for periodically determining whether or not the tip/ring line is coupled to the tip/ring port, the processor retaining the dialing mode bit setting while the tip/ring line remains connected.
14. An automatic dialing mode selection system comprising a processor, a tip/ring port adapted for coupling to a tip/ring line, a tone generator coupled to the tip/ring port for generating DTMF tones, a dial tone detector for detecting the presence of dial tone, a dial pulse signal generator, an electronic switch coupled to the tip/ring port, a power supply input port equipped to accept an input voltage, and a memory for storing a dialing mode bit specifying either a pulsed dialing mode to be implemented by the dial pulse signal generator or a touch-tone dialing mode to be implemented by the tone generator.
15. The automatic dialing mode selection system of Claim 14 wherein the processor is coupled to the tip/ring port and the power supply input port; the processor further comprising means for determining whether or not (i) the tip/ring line is coupled to the tip/ring port, and (ii) an input voltage is coupled to the power supply input port.
16. The automatic dialing mode selection system of Claim 15 wherein the processor is coupled to the electronic switch; the processor, upon first detecting that both (i) the tip/ring line is connected to the tip/ring port, and (ii) an input voltage is coupled to the power supply input port, activating the electronic switch to place the automatic dialing mode selection system in an off-hook condition with respect to the tip/ring line.
17. The automatic dialing mode selection system of Claim 16 wherein the tone generator generates a DTMF digit in response to the electronic switch placing the automatic dialing mode selection system in an off-hook condition.
18. The automatic dialing mode selection system of Claim 17 wherein the dial tone detector, responsive to the detection of dial tone on the tip/ring line, activates the processor such that the processor, responsive to the dial tone detector, sets the dialing mode bit to specify the pulsed dialing mode.
19. The automatic dialing mode selection system of Claim 17 wherein the dial tone detector, responsive to the detection of no dial tone on the tip/ring line, activates the processor such that the processor, responsive to the dial tone detector, sets the dialing mode bit to specify the touch-tone dialing mode.
20. The automatic dialing mode selection system of Claim 17 further comprising a memory for storing a dialing mode determination bit value specifying whether or not the dialing mode bit has been set subsequent to the coupling of a tip/ring line to the tip/ring port and also prior to the removal of the tip/ring line from the tip/ring port.
21. The automatic dialing mode selection system of Claim 19 wherein the processor sets the dialing mode at the time that the automatic dialing mode selection system is first connected to the tip-ring line, the processor retaining that dialing mode setting until the automatic dialing mode selection system is removed from the tip-ring line.
22. An automatic dialing mode selection method for use with a telephonic device having a processor, a power supply input port adapted for coupling to a voltage source, a tip/ring port adapted for coupling to a tip/ring line, a dual-tone, multi-frequency (DTMF) tone generator coupled to the tip/ring port for generating DTMF tones, a dial tone detector for detecting the presence of dial tone, a dial pulse signal generator, a memory that stores a dialing mode bit specifying either a pulsed dialing mode to be implemented by the dial pulse signal generator or a touch-tone dialing mode to be implemented by the DTMF tone generator, and a dialing device for accepting one or more entered digits and for dialing entered digits in a dialing mode specified by the dialing mode bit;
the method including the following steps:
(a) the processor checks for the existence of the following conditions: (i) the tip/ring line being coupled to the tip/ring port, (ii) a voltage source being coupled to the power supply input port, (iii) the telephonic device being in an off-hook condition, and (iv) a digit being entered into the dialing device;
(b) upon first detecting all of the conditions set forth in step (a), the processor activating the tone generator to generate a DTMF digit corresponding to the digit entered into the dialing device;
(d) the dial tone detector monitoring the tip/ring line for the presence of dial tone, (e) upon detection of dial tone at step (d), the processor setting the dialing mode bit to specify the pulsed dialing mode; or, upon no detection of dial tone at step (d), the processor setting the dialing mode bit to specify the touch-tone dialing mode.
the method including the following steps:
(a) the processor checks for the existence of the following conditions: (i) the tip/ring line being coupled to the tip/ring port, (ii) a voltage source being coupled to the power supply input port, (iii) the telephonic device being in an off-hook condition, and (iv) a digit being entered into the dialing device;
(b) upon first detecting all of the conditions set forth in step (a), the processor activating the tone generator to generate a DTMF digit corresponding to the digit entered into the dialing device;
(d) the dial tone detector monitoring the tip/ring line for the presence of dial tone, (e) upon detection of dial tone at step (d), the processor setting the dialing mode bit to specify the pulsed dialing mode; or, upon no detection of dial tone at step (d), the processor setting the dialing mode bit to specify the touch-tone dialing mode.
23. An automatic dialing mode selection method as set forth in Claim 22 wherein,after the performance of step (e), the existence of the tip/ring line being coupled to the tip/ring port is periodically monitored and, when the tip/ring line is not coupled to the tip/ring port, performing steps (a)-(e).
24. An automatic dialing mode selection method for use with a telephonic device having a processor, a tip/ring port adapted for coupling to a tip/ring line, a tone generator coupled to the tip/ring port for generating DTMF tones, a keypad for activating the tone generator, a dial tone detector for detecting the presence of dial tone, a dial pulse signal generator, an electronic switch coupled to the tip/ring port, and memory that stores a dialing mode bit specifying either a pulsed dialing mode to be implemented by the dial pulse signal generator or a touch-tone dialing mode to be implemented by the tone generator; the method including the following steps:
(a) activating the processor in response to (i) the tip/ring line being coupled to the tip/ring port, and (ii) the telephonic device being placed in an off-hook condition;
(b) activating the keypad to cause the tone generator to generate at least one DTMF digit;
(c) the dial tone detector monitoring the tip/ring line for the presence of dial tone;
(d) upon detection of dial tone at step (c), the processor setting the dialing mode bit to specify the pulsed dialing mode; or, upon no detection of dial tone at step (d), the processor setting the dialing mode bit to specify the touch-tone dialing mode.
(a) activating the processor in response to (i) the tip/ring line being coupled to the tip/ring port, and (ii) the telephonic device being placed in an off-hook condition;
(b) activating the keypad to cause the tone generator to generate at least one DTMF digit;
(c) the dial tone detector monitoring the tip/ring line for the presence of dial tone;
(d) upon detection of dial tone at step (c), the processor setting the dialing mode bit to specify the pulsed dialing mode; or, upon no detection of dial tone at step (d), the processor setting the dialing mode bit to specify the touch-tone dialing mode.
25. An automatic dialing mode selection method as set forth in Claim 24 for use with a telephonic device further comprising a memory that stores a dialing mode determination bit value specifying whether or not the dialing mode bit has been set subsequent to the coupling of a tip/ring line to the tip/ring port and also prior to the removal of the tip/ring line from the tip/ring port; the method further comprising the step of setting the dialing mode determination bit value to specify whether or not the dialing mode bit has been set.
26. A dialing mode selection method for use with a telephonic device connected to a tip-ring line, the telephonic device including dialing mode assessment circuitry, dialing mode setting circuitry, and a digit dialing device for dialing one or more user-selected digits in a dialing mode specified by the dialing mode setting circuitry, the method including the following steps:
(a) the dialing mode assessment circuitry determining the dialing mode supportedby the tip-ring line in response to (i) the telephonic device being placed in an off-hook condition, and (ii) a digit being dialed by the digit dialing device, wherein the dialing mode includes at least one of pulsed dialing and touch-tone dialing;
(b) the dialing mode setting circuitry, in response to the dialing mode assessment circuitry, setting the dialing mode of the telephonic device to specify the dialing mode supported by the tip-ring line.
(a) the dialing mode assessment circuitry determining the dialing mode supportedby the tip-ring line in response to (i) the telephonic device being placed in an off-hook condition, and (ii) a digit being dialed by the digit dialing device, wherein the dialing mode includes at least one of pulsed dialing and touch-tone dialing;
(b) the dialing mode setting circuitry, in response to the dialing mode assessment circuitry, setting the dialing mode of the telephonic device to specify the dialing mode supported by the tip-ring line.
27. An automatic dialing mode selection method as set forth in Claim 26 wherein the step of setting the dialing mode is performed the first time that a digit is entered into the dialing device subsequent to the telephonic device being connected to the tip-ring line, and the dialing mode remains so set until such time as the telephonic device is removed from the tip-ring line.
28. An automatic dialing mode selection method for use with a telephonic device having: (i) a processor, (ii) a tip/ring port adapted for coupling to a tip/ring line, (iii) a dialing device for accepting one or more entered digits and for dialing the entered digits, the dialing device including a tone generator coupled to the tip/ring port for generating DTMF tones and a dial pulse signal generator for generating pulsed dialing signals; (iv) a dial tone detector for detecting the presence of dial tone, and (v) memory that stores a dialing mode bit specifying either a pulsed dialing mode to be implemented by the dial pulse signal generator or a touch-tone dialing mode to be implemented by the tone generator; the method including the following steps:
(a) the processor determining whether or not (i) the tip/ring line is coupled to the tip/ring port, (ii) the telephonic device is off-hook, and (iii) at least a first arbitrarily-selected digit is entered into the dialing device;
(b) upon first detecting that the tip/ring line is connected to the tip/ring port, the telephonic device is off-hook, and at least the first arbitrarily-selected digit is entered into the dialing device, the processor activating the tone generator to generate a DTMF digit corresponding to the first arbitrarily-selected digit;
(c) the dial tone detector monitoring the tip/ring line for the presence of dial tone;
(d) upon detection of dial tone at step (c), the processor setting the dialing mode bit to specify the pulsed dialing mode; or, upon no detection of dial tone at step (c), the processor setting the dialing mode bit to specify the touch-tone dialing mode.
(a) the processor determining whether or not (i) the tip/ring line is coupled to the tip/ring port, (ii) the telephonic device is off-hook, and (iii) at least a first arbitrarily-selected digit is entered into the dialing device;
(b) upon first detecting that the tip/ring line is connected to the tip/ring port, the telephonic device is off-hook, and at least the first arbitrarily-selected digit is entered into the dialing device, the processor activating the tone generator to generate a DTMF digit corresponding to the first arbitrarily-selected digit;
(c) the dial tone detector monitoring the tip/ring line for the presence of dial tone;
(d) upon detection of dial tone at step (c), the processor setting the dialing mode bit to specify the pulsed dialing mode; or, upon no detection of dial tone at step (c), the processor setting the dialing mode bit to specify the touch-tone dialing mode.
29. An automatic dialing mode selection method as set forth in Claim 28 for use with a telephonic device further comprising a memory that stores a dialing mode determination bit value specifying whether or not the dialing mode bit has been set subsequent to the coupling of a tip/ring line to the tip/ring port and also prior to the removal of the tip/ring line from the tip/ring port;
step (d) further comprising the step of setting the dialing mode determination bit value to specify that the dialing mode bit has been set;
step (e), following step (d): setting the dialing mode determination bit, when the tip/ring line is removed from the tip/ring port, to a value indicating that the dialing mode needs to be determined anew;
and then going back to step (a).
step (d) further comprising the step of setting the dialing mode determination bit value to specify that the dialing mode bit has been set;
step (e), following step (d): setting the dialing mode determination bit, when the tip/ring line is removed from the tip/ring port, to a value indicating that the dialing mode needs to be determined anew;
and then going back to step (a).
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US56072295A | 1995-11-20 | 1995-11-20 | |
| US560,722 | 1995-11-20 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2186794A1 true CA2186794A1 (en) | 1997-05-21 |
Family
ID=24239078
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2186794 Abandoned CA2186794A1 (en) | 1995-11-20 | 1996-09-30 | Automatic dialing mode selection |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JPH09172483A (en) |
| BR (1) | BR9605638A (en) |
| CA (1) | CA2186794A1 (en) |
| MX (1) | MX9605577A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109561194A (en) * | 2018-12-27 | 2019-04-02 | 深圳市新国都支付技术有限公司 | A kind of POS machine Dialing Method and device |
-
1996
- 1996-09-30 CA CA 2186794 patent/CA2186794A1/en not_active Abandoned
- 1996-11-14 MX MX9605577A patent/MX9605577A/en unknown
- 1996-11-19 JP JP30761396A patent/JPH09172483A/en active Pending
- 1996-11-20 BR BR9605638A patent/BR9605638A/en not_active Application Discontinuation
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109561194A (en) * | 2018-12-27 | 2019-04-02 | 深圳市新国都支付技术有限公司 | A kind of POS machine Dialing Method and device |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH09172483A (en) | 1997-06-30 |
| MX9605577A (en) | 1997-05-31 |
| BR9605638A (en) | 1998-08-18 |
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| Date | Code | Title | Description |
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| FZDE | Dead |
Effective date: 19990930 |