CA1310066C - Mobile radio interface - Google Patents
Mobile radio interfaceInfo
- Publication number
- CA1310066C CA1310066C CA 613824 CA613824A CA1310066C CA 1310066 C CA1310066 C CA 1310066C CA 613824 CA613824 CA 613824 CA 613824 A CA613824 A CA 613824A CA 1310066 C CA1310066 C CA 1310066C
- Authority
- CA
- Canada
- Prior art keywords
- interface
- receive
- transmit
- radio
- port
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
- H04W88/02—Terminal devices
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/38—Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of transmitting and receiving
- H04B1/40—Circuits
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- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Mobile Radio Communication Systems (AREA)
Abstract
ABSTRACT
An electronic interface for use with a mobile radio transceiver as part of a standard telephone network to permit the mobile radio to transmit and automatically or manually receive voice messages and analog data information. The interface is provided with two or more receive/transmit ports and can accommodate sequential reception of both voice and analog data information during the same call. Additionally, the interface in the receive mode can be programmed to select the appropriate port by the originator of the call.
An electronic interface for use with a mobile radio transceiver as part of a standard telephone network to permit the mobile radio to transmit and automatically or manually receive voice messages and analog data information. The interface is provided with two or more receive/transmit ports and can accommodate sequential reception of both voice and analog data information during the same call. Additionally, the interface in the receive mode can be programmed to select the appropriate port by the originator of the call.
Description
1 3 ~
This invention relates to an electronic interface for use with a mobile radio transceiver as part of a telephone network to permit transmission and automatic/manual reception of both voice and analog data information.
This interface accommodates units normally connected to standard telephone land line networks such as telephone units, cordless telephones, answering machines, facsimiles, computer modems, etc.
Both simplex and duplex radio transceivers make up the family of mobile radios. The interface accommodates these various styles of radio transceivers using MTS, IMTS, *NOVATEL 400 MHZ Cellular and the 800 MHZ Cellular.
Mobile radio units are used extensively in remote areas in which conventional telephone lines are not available. Frequently, for example, oil wells are located in areas which are not serviced by the telephone network.
The rapidly expanding field of communication by data transmission means such as facsimile and computer modems have made available to surveyors, oil drilling operators, etc., a valuable tool in providing instantaneous information from one site to another. The lack of a telephone system to remote areas has limited the efficiency of this data transmission process.
In Canadian Patent 1,223,059 which issued June 16, 1987 to Polanski Electronics Limited, there is disclosed an interface to permit transmission of signals between a data transfer unit and a radio transceiver. The 1,223,059 patent discloses an interface having a receiving circuit and a transmitting circuit, an analog data bus to transfer data between the device and the circuits and a switch to connect either the receive circuit or the transmit circuit to the device.
The present invention overcomes the requirement of the switch means by having both the receive and transmit circuits operationally connected between the device and the radio. The device of the present invention further provides * - Trade-mark 131~S
a selectlon mode whereby the caller may dlrect the lnterface unlt to couple the radlo to one or more receive units such as a facslmlle unlt, answering machlne or computer modem. The present interface also allow~ for the un-attended reception of an lncoming radlo call to an answering machine or a data devlce. Presently, incoming calls must be answered by the radlo user to accept the call and to manually acti.vate any devlces connected, such as facslmiles. After data completlon the operator would then have to place the radio on-hook. The 1~ devlce of the present invention further provides loop current for detectlon of a load on either port to connect that unit to the receive and transmit circuits of the lnterface. This elimlnates the need for manually switching from VOICE TO DATA
to connect the device. Control of the selection means is performed by the sender by transmitting a code, such as a selected keypad on a telephone to make the appropriate selectlon. In the transmit mode, the call is placed as in normal radlo operatlon and when contact with the unit at the answering end is completed, the facslmile or modem is connected for normal transmission. Therefore, in accordance wlth the pre~ent lnvention, there is provlded an interface means for use with a mo~lle radio to permit the radio to receive and transmlt data and voice information, the inter-face means includes connector means for connectlng the interface to the radio, port select means including means to selectlvely couple the interface means to one or more means to recelve or transmlt data and voice information, converter means adapted to interconnect the connector means to the port select means, circult means responsive to a receive single 3~ from the radlo operable to select receive data information means coupled to the port select means, circuit means respons~ve to transmit signals from the transmit information means to operate the radlo in a transmit mode, and a power supply to provide operating power to the interface.
The preferred embodiment of the present invention will ~,, ~ .
now be descrlbed in greater detail with reference to the appended figures whereln:
Flgure 1 is an overall system ~lock diagram;
Figure 2 is a block dlagram of the interface of the present lnven~ion;
Figure 3 is an illustration of the radio connections;
Flgure 4 illustrates the 2 to 4 wlre converter;
Figure 5 is a flow chart of the lnterface logic;
Figure 6 lS a clrcuit dlagram of the inter~ace power supply; and, FlgUre 7 lS a circult dlagram of the interface logic board.
Referring in1tlally to Figure 1, there is illustrated, in block form, the overall relationship of the components o~
the system according to the present invention. It is assumed that within the operat1on of the telephone company 10, there is a mobile radio facility including a mobile radio operator 12. Many of the present mobile radio systems rely on a central operator to intercept and pass through calls orlgin-atlng from a remote station, and in those cases, the systemo~ the present invention also relies on the mobile operator.
A standard land line telephone system 14 links the telephone company 10 to the main office or base station 16. The mobile unit 24 i~ located at a remote station 18 without normal telephone servlce. Calls originating from the mobile radio are transmitted from the mobile's antennae 20 to the trans-mlssion tower 22 and, hence, to the mobile operator 12. On some simplex and duplex radio systems there is no telephone operator required to ass1st in placing calls to or from a mobile radlo, such as in cellular radio. The present interface will transmlt and receive data without -the neces-slty o~ the telephone operator intervention.
The mobile station 18 as shown in the block d1agram includes the mobile radio 24 with antennae 20, the interface 26, which is the subject of the present invention, and a facs1mlle machlne 2~ and/or an an~wering machine 30. It is al~o w1thin the scope of this lnvention that the interface unit 26 may be connected to a computer modem ~not shown) and other such devlces whlch may be connected to a telephone unit.
When the mob1le radlo 24 is to be used as a facsimlle sendlng devlce, normal radio connectlon is made to the mobile operator 12 who, ln turn, patches the call through to the telephone ln the base statlon 16. When contact has been completed wlth the base station telephone, the interface unit 26 is actlvated by the operator and the facsimile message is transmitted through the system in an analogous manner to messages whlch are transmitted over a land line telephone system. Slnce communicat1on to the base station may require the asslstance of the mobile operator, it is not possible in tho~e cases for the present system to program -the facsimlle machine to automatlcally send or transmit data information.
The system, however, does permit automatic and unat-tended reception of audio messages or data transmissions.
The call orIg1nator at the base off1ce 16 makes contact by telephone to the mobile operator 12 who then patches the call through to the mobile radlo 24 in the normal manner. The mob1le radlo 24 receives the telephone ring signal and, provid1ng the lnterface 26 lS powered on and the facsimile unit 28 and answering machlne 30 are on hook, the interface will connect the lncoming call to PORT A. If the operator of the radlo transceiver wishes to leave a recorded message the interface 26 may be set up to have the answering unit 30 answer automatlcally to recelve the call and in turn, provide the caller with a recorded message. The interface 26 may also be programmed to have the answerlng machine 30 automati-cally recelve the call and to, in turn, provide the caller Wl th a recorded message as to the proper procedures to follow in sending the facsimile transmission. This instruction could be that pressing # 8 on the caller's touch-tone phone ~ 3~
would actlvate the facslmile ln PORT B ~o connect to the transcelver for facslmlle data trans~er.
The overall systern wlll now be descrlbed in greater detail wlth reference to the lnterface block diagram shown in Flgure 2.
The radio connectlon sectlon 40 includes a multi pin connector whlch provides all necessary connections. Figure 3 lllustrates the relatlonship between a conventional radio connector and the connections to the interface unlt.
Tne audlo receive signal 46 from the radlo and the transmit signal 48 to the radio pass from the connector to the two-to-four wlre converter 50 b~ way of an audio buffer 44. The audio buffer provides gain control on the receive path to ad~ust the incoming signal to an optimum level at the input to the facslmile machine. The audio buffer 44 also includes means to adjust the transmit level in order to accommodate differlng levels required for different radios.
This adjustment lS set by the installer according to specifi-cations. The audio buffer 44 also includes operational 2~ ampliflers to reject power supply noise in order to aid in nolse reduction. The receive and transmit signals are fed to the two-to-four wire converter 50 which converts the separate receive and transmit paths of the radio to the single two wire path of a standard telephone. The converter design is based on a subscriber loop interface circuit 52 (SLIC) which is available from manufacturers in the form of an integrated circuit requiring only a few auxiliary components. The converter performs the functions of telephone hook switch detection, ring relay driving, and two-to-four wire conver-sion. The two-to-four wire converter is shown in greater detail in the block diagram of Figure 4.
In Figure 4, the balance circuit 54 associated with the SLIC is required to provide an impedance match between the interface and the telephone equipment. This is a simple R-C
network. The converter must provide suffic1ent channel 6 ~ 3 ~
separation and compensation such that receive signals do not get retransmitted causing erroneous activations of the voice activated circuit.
Transient protection 56 on the telephone side is required to protect the interface from inductive switching spikes. This will be in the form of flyback diodes with performance equivalent to a *Motorola MDA 220/210G.
The ring relay 58 is controlled by the SLIC 52 which, in turn, is controlled by the logic section 70 to be described hereinafter. The ring relay 58 switches the telephone feed between normal loop voltage and the ringing voltage. An important function of the SLIC 52 is to switch off the ringing voltage when the telephone service goes off hook.
Returning to Figure 2, the port select relay and driver 60 is a simple double pole/double throw switch that connects either PORT A or PORT B to the two-to-four wire converter 50. The port selection command is a logic level signal from the logic section 70. If necessary, this logic signal could be boosted by a relay driver to give adequate current drive to the relay coil 58. The relay must be chosen to withstand the ringing and switching voltages on the telephone interface and the shock and vibration of the mobile environment.
The power supply 80 is designed to provide sufficient loop voltage and loop current to operate the system. The loop voltage i5 generated using a switching power supply.
The ring generator 82 requires a minimum voltage of 50 volts RMS superimposed on the loop voltage. The ringing voltage is a rough sine-wave at typically 2OHZ. It can vary peak-peak with a nominal voltage of 60 volts p.p. The voltage of the rails will be chosen to give a -48 volt plus or minus 6 volt DC offset.
The VOX circuit 90 detects transmitted levels from both the facsimile and the answering machine connected to PORT A
or PORT B. Levels greater than a threshold cause the push to talk button on the radio to be activated. Any audio level * - Trade-mark ' ' ':
a~ove the threshold lnput triggers the push to talk on the rad1o. The c1rcult has an adjustment for minimum on time (nom1nally 2 seconds) and a separate adjustment for turn off tlme tafter the on time has expired - nominally 0 2 seconds) us1ng flxed res1stors. The threshold is adjustable by the installer.
The call and tone detector l00 sets a call alert signal 102 to a loglc high when the received audio level reaches a factory set threshold while the selected port is on hook.
Call detect1on is performed using an op amp comparator with a filtered output to reject spurious response. The tone detector sets a tone detected s1gnal 104 to a logic high when a part1cular frequency is detected in the received audio.
The specif lC frequency used is chosen for ease of implementa-t1on in the absence of other operational considerations.
The logic section 70 controls the operation of the elements within the interface unit. The logic section follows the protocol shown in the interface logic flow chart of Figure 5. The control panel ll0 allows the operator to manually reset or power off/on the interface. The control panel also contains visual indicators in the form of LEDs to indicate to the operator the status of the operation.
For greater detail with respect to the interface circuit and the power supply, reference may be made to the detailed circuit diagrams shown in Figures 6 and 7.
For operation of a call originating from the facsimile, the interface unit can be powered off or on. The call is established in the conventional manner using the mobile radio including confirmation that another facsimile machine is 3~ connected at the base station. At power-up PORT A is selected by default and at the end of every call handled by the interface, the unit automatically returns to a PORT A
select. It is to be understood that either PORT A or PORT B
can accommodate either a facsimile unit, an answering machine or a computer modem. The port required for the send opera-a ~ 3 tlon is selected by the activation of the unit connected tothat port. The fac~lmile unlt lS thus operated in the manual mode. When the facslmile unit goes off hook, the radio cradle switch is activated (regardless of whether the handset is in the cradle or not), and the radlo handset is usually dlsabled, and the microphone insulated as not to transmit induced nolse onto the transmit data. This may vary depend-lng on the style of radio. The audio circuits are then automatically dlverted to -the interface, and data transmis-sion can commence. The voice activated switch (VOX circuit)detects the presence of a transmit audio signal and controls the push to talk input to the radio accordingly.
Upon completion of the facsimile transmission, the facslmile unit automatically hangs up or goes on hook. At this time, the interface unit can be turned off if desired by the operator and the radio is enabled for conventional use.
Incoming calls may be received in either manual mode or automatic mode. In manual mode, incoming calls for conversa-tion can be handled in the normal manner through the handset, providing that the loop interface is not powered up. If the interface is powered up, it will ring the selected port when an incoming call is detected. The device on that port may answer the call before the user and i it does, the radio's handset may be disabled. In this instance, -the user can then either disable the interface and use the radio in the conventional method or allow the device to operate and handle the call automatically.
For automatic reception, the interface unit is powered up and both ports are in the on hook condition. An incoming call generates a tone on the speaker, and when the interface detects this tone, the ringing process is initiated on the selected port. As indicated previously, PORT A is selected by default at power up and at the end of each call handled by the lnterface. If the selected port does not answer (go off hook) within several rings (7), the interface selects PORT A
'~' 1 3 ~
and returns to the ready state. If the selected port goes off hook, the radlo cradle switch is actlvated (regardless of whether the handset is in the cradle or not), the radio handset is usually disabled, the audio circuits are automati-cally diverted to the interface and transmission can com-mence. Once the call has been established to the selected port, the calling party can select the other port by pushing a selected digit, for example, keypad # 8 on the touch tone phone. Upon reception of that tone, the interface switches to the other port and restarts the ringing process. If the other port does not answer within five rings, the call is terminated, PORT A is selected, and the interface returns to the ready state. This provision for switching ports remotely has been implemented so that an answering machine can perform its usual function of transmitting and receiving messages, and also ~o instruct the caller on how to leave a facsimile message. Thus, both a voice and facsimile message can be left during the same incoming call.
~lthough the foregoing description has been directed primarily to facsimile units and answering machines, it is to be understood that the interface can be programmed to access a computer modem connected to either port. It is also within the scope of the invention to provide more than two ports such that a facsimile unit, an answering machine and a computer modem and other analog data or voice devices normally assoclated with telephone networks can be connected to the interface unit and, hence, accessible by the mobile radio. For example, a cordless phone has been tested on the interface and it adds extra features to the interface systems. It allows a remote answer capability to the radio if, the caller is physically away from the radio. The system is limited mainly by the working range of the cordless phone.
On some radio transceivers, placing a call is also available through the cordless phone.
Also, an answering machine that can be accessed by a ~ 3 ~
remote beeper can offer the operator a system which he/she can retrleve their message by calling their own radio and after the answerlng machine answers activate their remote beeper.
While there has been shown and described a preferred embodiment of the invention, it will be appreciated that various modifications and adaptations of the invention will become readily apparent to those skilled in the art and it is intended that such obvious modifications and adaptation be 1~ encompassed Wl thin the claims appended hereto.
.
.
This invention relates to an electronic interface for use with a mobile radio transceiver as part of a telephone network to permit transmission and automatic/manual reception of both voice and analog data information.
This interface accommodates units normally connected to standard telephone land line networks such as telephone units, cordless telephones, answering machines, facsimiles, computer modems, etc.
Both simplex and duplex radio transceivers make up the family of mobile radios. The interface accommodates these various styles of radio transceivers using MTS, IMTS, *NOVATEL 400 MHZ Cellular and the 800 MHZ Cellular.
Mobile radio units are used extensively in remote areas in which conventional telephone lines are not available. Frequently, for example, oil wells are located in areas which are not serviced by the telephone network.
The rapidly expanding field of communication by data transmission means such as facsimile and computer modems have made available to surveyors, oil drilling operators, etc., a valuable tool in providing instantaneous information from one site to another. The lack of a telephone system to remote areas has limited the efficiency of this data transmission process.
In Canadian Patent 1,223,059 which issued June 16, 1987 to Polanski Electronics Limited, there is disclosed an interface to permit transmission of signals between a data transfer unit and a radio transceiver. The 1,223,059 patent discloses an interface having a receiving circuit and a transmitting circuit, an analog data bus to transfer data between the device and the circuits and a switch to connect either the receive circuit or the transmit circuit to the device.
The present invention overcomes the requirement of the switch means by having both the receive and transmit circuits operationally connected between the device and the radio. The device of the present invention further provides * - Trade-mark 131~S
a selectlon mode whereby the caller may dlrect the lnterface unlt to couple the radlo to one or more receive units such as a facslmlle unlt, answering machlne or computer modem. The present interface also allow~ for the un-attended reception of an lncoming radlo call to an answering machine or a data devlce. Presently, incoming calls must be answered by the radlo user to accept the call and to manually acti.vate any devlces connected, such as facslmiles. After data completlon the operator would then have to place the radio on-hook. The 1~ devlce of the present invention further provides loop current for detectlon of a load on either port to connect that unit to the receive and transmit circuits of the lnterface. This elimlnates the need for manually switching from VOICE TO DATA
to connect the device. Control of the selection means is performed by the sender by transmitting a code, such as a selected keypad on a telephone to make the appropriate selectlon. In the transmit mode, the call is placed as in normal radlo operatlon and when contact with the unit at the answering end is completed, the facslmile or modem is connected for normal transmission. Therefore, in accordance wlth the pre~ent lnvention, there is provlded an interface means for use with a mo~lle radio to permit the radio to receive and transmlt data and voice information, the inter-face means includes connector means for connectlng the interface to the radio, port select means including means to selectlvely couple the interface means to one or more means to recelve or transmlt data and voice information, converter means adapted to interconnect the connector means to the port select means, circult means responsive to a receive single 3~ from the radlo operable to select receive data information means coupled to the port select means, circuit means respons~ve to transmit signals from the transmit information means to operate the radlo in a transmit mode, and a power supply to provide operating power to the interface.
The preferred embodiment of the present invention will ~,, ~ .
now be descrlbed in greater detail with reference to the appended figures whereln:
Flgure 1 is an overall system ~lock diagram;
Figure 2 is a block dlagram of the interface of the present lnven~ion;
Figure 3 is an illustration of the radio connections;
Flgure 4 illustrates the 2 to 4 wlre converter;
Figure 5 is a flow chart of the lnterface logic;
Figure 6 lS a clrcuit dlagram of the inter~ace power supply; and, FlgUre 7 lS a circult dlagram of the interface logic board.
Referring in1tlally to Figure 1, there is illustrated, in block form, the overall relationship of the components o~
the system according to the present invention. It is assumed that within the operat1on of the telephone company 10, there is a mobile radio facility including a mobile radio operator 12. Many of the present mobile radio systems rely on a central operator to intercept and pass through calls orlgin-atlng from a remote station, and in those cases, the systemo~ the present invention also relies on the mobile operator.
A standard land line telephone system 14 links the telephone company 10 to the main office or base station 16. The mobile unit 24 i~ located at a remote station 18 without normal telephone servlce. Calls originating from the mobile radio are transmitted from the mobile's antennae 20 to the trans-mlssion tower 22 and, hence, to the mobile operator 12. On some simplex and duplex radio systems there is no telephone operator required to ass1st in placing calls to or from a mobile radlo, such as in cellular radio. The present interface will transmlt and receive data without -the neces-slty o~ the telephone operator intervention.
The mobile station 18 as shown in the block d1agram includes the mobile radio 24 with antennae 20, the interface 26, which is the subject of the present invention, and a facs1mlle machlne 2~ and/or an an~wering machine 30. It is al~o w1thin the scope of this lnvention that the interface unit 26 may be connected to a computer modem ~not shown) and other such devlces whlch may be connected to a telephone unit.
When the mob1le radlo 24 is to be used as a facsimlle sendlng devlce, normal radio connectlon is made to the mobile operator 12 who, ln turn, patches the call through to the telephone ln the base statlon 16. When contact has been completed wlth the base station telephone, the interface unit 26 is actlvated by the operator and the facsimile message is transmitted through the system in an analogous manner to messages whlch are transmitted over a land line telephone system. Slnce communicat1on to the base station may require the asslstance of the mobile operator, it is not possible in tho~e cases for the present system to program -the facsimlle machine to automatlcally send or transmit data information.
The system, however, does permit automatic and unat-tended reception of audio messages or data transmissions.
The call orIg1nator at the base off1ce 16 makes contact by telephone to the mobile operator 12 who then patches the call through to the mobile radlo 24 in the normal manner. The mob1le radlo 24 receives the telephone ring signal and, provid1ng the lnterface 26 lS powered on and the facsimile unit 28 and answering machlne 30 are on hook, the interface will connect the lncoming call to PORT A. If the operator of the radlo transceiver wishes to leave a recorded message the interface 26 may be set up to have the answering unit 30 answer automatlcally to recelve the call and in turn, provide the caller with a recorded message. The interface 26 may also be programmed to have the answerlng machine 30 automati-cally recelve the call and to, in turn, provide the caller Wl th a recorded message as to the proper procedures to follow in sending the facsimile transmission. This instruction could be that pressing # 8 on the caller's touch-tone phone ~ 3~
would actlvate the facslmile ln PORT B ~o connect to the transcelver for facslmlle data trans~er.
The overall systern wlll now be descrlbed in greater detail wlth reference to the lnterface block diagram shown in Flgure 2.
The radio connectlon sectlon 40 includes a multi pin connector whlch provides all necessary connections. Figure 3 lllustrates the relatlonship between a conventional radio connector and the connections to the interface unlt.
Tne audlo receive signal 46 from the radlo and the transmit signal 48 to the radio pass from the connector to the two-to-four wlre converter 50 b~ way of an audio buffer 44. The audio buffer provides gain control on the receive path to ad~ust the incoming signal to an optimum level at the input to the facslmile machine. The audio buffer 44 also includes means to adjust the transmit level in order to accommodate differlng levels required for different radios.
This adjustment lS set by the installer according to specifi-cations. The audio buffer 44 also includes operational 2~ ampliflers to reject power supply noise in order to aid in nolse reduction. The receive and transmit signals are fed to the two-to-four wire converter 50 which converts the separate receive and transmit paths of the radio to the single two wire path of a standard telephone. The converter design is based on a subscriber loop interface circuit 52 (SLIC) which is available from manufacturers in the form of an integrated circuit requiring only a few auxiliary components. The converter performs the functions of telephone hook switch detection, ring relay driving, and two-to-four wire conver-sion. The two-to-four wire converter is shown in greater detail in the block diagram of Figure 4.
In Figure 4, the balance circuit 54 associated with the SLIC is required to provide an impedance match between the interface and the telephone equipment. This is a simple R-C
network. The converter must provide suffic1ent channel 6 ~ 3 ~
separation and compensation such that receive signals do not get retransmitted causing erroneous activations of the voice activated circuit.
Transient protection 56 on the telephone side is required to protect the interface from inductive switching spikes. This will be in the form of flyback diodes with performance equivalent to a *Motorola MDA 220/210G.
The ring relay 58 is controlled by the SLIC 52 which, in turn, is controlled by the logic section 70 to be described hereinafter. The ring relay 58 switches the telephone feed between normal loop voltage and the ringing voltage. An important function of the SLIC 52 is to switch off the ringing voltage when the telephone service goes off hook.
Returning to Figure 2, the port select relay and driver 60 is a simple double pole/double throw switch that connects either PORT A or PORT B to the two-to-four wire converter 50. The port selection command is a logic level signal from the logic section 70. If necessary, this logic signal could be boosted by a relay driver to give adequate current drive to the relay coil 58. The relay must be chosen to withstand the ringing and switching voltages on the telephone interface and the shock and vibration of the mobile environment.
The power supply 80 is designed to provide sufficient loop voltage and loop current to operate the system. The loop voltage i5 generated using a switching power supply.
The ring generator 82 requires a minimum voltage of 50 volts RMS superimposed on the loop voltage. The ringing voltage is a rough sine-wave at typically 2OHZ. It can vary peak-peak with a nominal voltage of 60 volts p.p. The voltage of the rails will be chosen to give a -48 volt plus or minus 6 volt DC offset.
The VOX circuit 90 detects transmitted levels from both the facsimile and the answering machine connected to PORT A
or PORT B. Levels greater than a threshold cause the push to talk button on the radio to be activated. Any audio level * - Trade-mark ' ' ':
a~ove the threshold lnput triggers the push to talk on the rad1o. The c1rcult has an adjustment for minimum on time (nom1nally 2 seconds) and a separate adjustment for turn off tlme tafter the on time has expired - nominally 0 2 seconds) us1ng flxed res1stors. The threshold is adjustable by the installer.
The call and tone detector l00 sets a call alert signal 102 to a loglc high when the received audio level reaches a factory set threshold while the selected port is on hook.
Call detect1on is performed using an op amp comparator with a filtered output to reject spurious response. The tone detector sets a tone detected s1gnal 104 to a logic high when a part1cular frequency is detected in the received audio.
The specif lC frequency used is chosen for ease of implementa-t1on in the absence of other operational considerations.
The logic section 70 controls the operation of the elements within the interface unit. The logic section follows the protocol shown in the interface logic flow chart of Figure 5. The control panel ll0 allows the operator to manually reset or power off/on the interface. The control panel also contains visual indicators in the form of LEDs to indicate to the operator the status of the operation.
For greater detail with respect to the interface circuit and the power supply, reference may be made to the detailed circuit diagrams shown in Figures 6 and 7.
For operation of a call originating from the facsimile, the interface unit can be powered off or on. The call is established in the conventional manner using the mobile radio including confirmation that another facsimile machine is 3~ connected at the base station. At power-up PORT A is selected by default and at the end of every call handled by the interface, the unit automatically returns to a PORT A
select. It is to be understood that either PORT A or PORT B
can accommodate either a facsimile unit, an answering machine or a computer modem. The port required for the send opera-a ~ 3 tlon is selected by the activation of the unit connected tothat port. The fac~lmile unlt lS thus operated in the manual mode. When the facslmile unit goes off hook, the radio cradle switch is activated (regardless of whether the handset is in the cradle or not), and the radlo handset is usually dlsabled, and the microphone insulated as not to transmit induced nolse onto the transmit data. This may vary depend-lng on the style of radio. The audio circuits are then automatically dlverted to -the interface, and data transmis-sion can commence. The voice activated switch (VOX circuit)detects the presence of a transmit audio signal and controls the push to talk input to the radio accordingly.
Upon completion of the facsimile transmission, the facslmile unit automatically hangs up or goes on hook. At this time, the interface unit can be turned off if desired by the operator and the radio is enabled for conventional use.
Incoming calls may be received in either manual mode or automatic mode. In manual mode, incoming calls for conversa-tion can be handled in the normal manner through the handset, providing that the loop interface is not powered up. If the interface is powered up, it will ring the selected port when an incoming call is detected. The device on that port may answer the call before the user and i it does, the radio's handset may be disabled. In this instance, -the user can then either disable the interface and use the radio in the conventional method or allow the device to operate and handle the call automatically.
For automatic reception, the interface unit is powered up and both ports are in the on hook condition. An incoming call generates a tone on the speaker, and when the interface detects this tone, the ringing process is initiated on the selected port. As indicated previously, PORT A is selected by default at power up and at the end of each call handled by the lnterface. If the selected port does not answer (go off hook) within several rings (7), the interface selects PORT A
'~' 1 3 ~
and returns to the ready state. If the selected port goes off hook, the radlo cradle switch is actlvated (regardless of whether the handset is in the cradle or not), the radio handset is usually disabled, the audio circuits are automati-cally diverted to the interface and transmission can com-mence. Once the call has been established to the selected port, the calling party can select the other port by pushing a selected digit, for example, keypad # 8 on the touch tone phone. Upon reception of that tone, the interface switches to the other port and restarts the ringing process. If the other port does not answer within five rings, the call is terminated, PORT A is selected, and the interface returns to the ready state. This provision for switching ports remotely has been implemented so that an answering machine can perform its usual function of transmitting and receiving messages, and also ~o instruct the caller on how to leave a facsimile message. Thus, both a voice and facsimile message can be left during the same incoming call.
~lthough the foregoing description has been directed primarily to facsimile units and answering machines, it is to be understood that the interface can be programmed to access a computer modem connected to either port. It is also within the scope of the invention to provide more than two ports such that a facsimile unit, an answering machine and a computer modem and other analog data or voice devices normally assoclated with telephone networks can be connected to the interface unit and, hence, accessible by the mobile radio. For example, a cordless phone has been tested on the interface and it adds extra features to the interface systems. It allows a remote answer capability to the radio if, the caller is physically away from the radio. The system is limited mainly by the working range of the cordless phone.
On some radio transceivers, placing a call is also available through the cordless phone.
Also, an answering machine that can be accessed by a ~ 3 ~
remote beeper can offer the operator a system which he/she can retrleve their message by calling their own radio and after the answerlng machine answers activate their remote beeper.
While there has been shown and described a preferred embodiment of the invention, it will be appreciated that various modifications and adaptations of the invention will become readily apparent to those skilled in the art and it is intended that such obvious modifications and adaptation be 1~ encompassed Wl thin the claims appended hereto.
.
.
Claims (12)
1. Interface means for use with a simplex or duplex radio to permit said radio to receive and transmit voice and data information, said interface means including:
connector means for connecting said interface to said radio;
port select means including means to selectively couple said interface means to one or more means to receive or transmit voice and data information;
converter means adapted to connect, receive and transmit lines from said connector means to said port select means;
circuit means responsive to a receive signal from said radio operable to select receive data information means coupled to said port select means;
circuit means responsive to transmit signals from said transmit information means to operate said radio in a transmit mode, and power supply to provide operating power to said inter-face.
connector means for connecting said interface to said radio;
port select means including means to selectively couple said interface means to one or more means to receive or transmit voice and data information;
converter means adapted to connect, receive and transmit lines from said connector means to said port select means;
circuit means responsive to a receive signal from said radio operable to select receive data information means coupled to said port select means;
circuit means responsive to transmit signals from said transmit information means to operate said radio in a transmit mode, and power supply to provide operating power to said inter-face.
2. Interface means according to claim 1 wherein said means to receive or transmit voice and data information is a facsimile unit.
3. Interface means according to claim 1 wherein said means to receive or transmit voice and data information is a standard telephone.
4. Interface means according to claim 1 wherein said means to receive or transmit data and voice information is a modem to access a computer.
5. Interface means operable in association with a simplex or duplex radio to permit said radio to transmit and receive data and voice information, said interface means including:
connector means to facilitate connection of said interface to said radio;
port select means adapted to respond to an input signal so as it selectively couple said interface to one or more means to receive or transmit data and voice information;
two-to-four wire converter to connect receive and transmit lines from said connector means to said port select means;
call and tone detect means responsive to a receive signal from said radio to cause said interface to assume a transmission receive mode;
logic means operatively connected to said call and tone detect means to interegate said receive signal and to instruct said port select means to connect said interface to an appropriate one of said means to receive or transmit data and voice information depending on said receive signal;
circuit means responsive to an audio signal generated by said means to receive or transmit data and voice information to set said radio into a transmit mode; and a power supply to provide operating power to said interface.
connector means to facilitate connection of said interface to said radio;
port select means adapted to respond to an input signal so as it selectively couple said interface to one or more means to receive or transmit data and voice information;
two-to-four wire converter to connect receive and transmit lines from said connector means to said port select means;
call and tone detect means responsive to a receive signal from said radio to cause said interface to assume a transmission receive mode;
logic means operatively connected to said call and tone detect means to interegate said receive signal and to instruct said port select means to connect said interface to an appropriate one of said means to receive or transmit data and voice information depending on said receive signal;
circuit means responsive to an audio signal generated by said means to receive or transmit data and voice information to set said radio into a transmit mode; and a power supply to provide operating power to said interface.
6. Interface means as claimed in claim 5 wherein said port select means comprises a relay to selectively connect said interface to a first port or a second port.
7. Interface means as claimed in claim 6 wherein said first port is coupled to a telephone answering unit and said second port is coupled to a facsimile unit.
8. Interface means as claimed in claim 5 wherein said first port or said second port is coupled to a computer modem.
9. Interface means as claimed in claim 5 wherein said means to receive or transmit data and voice information is a cordless telephone.
10. An electronic interface operable in association with a simplex or duplex mobile radio to permit said radio to transmit and automatically or manually receive data and/or voice information, said interface including:
a multi pin connector to interconnect said interface to said radio;
a port select circuit including relay means operable in response to an input signal to selectively couple said interface to one of said ports to which means to receive or transmit data and/or voice information is connected;
two-to-four wire converter to connect receive and transmit paths from said connector to said port select circuit;
call and tone detect means responsive to a receive message from said radio to cause said interface to assume a receive transmission mode;
logic means operatively connected to said call and tone detect means to interegate said receive message and to instruct said port select circuit to connect said interface to an appropriate one of said means to receive or transmit voice and data information depending on said receive message;
circuit means responsive to an audio signal from said means to receive and transmit voice and data information to set said radio into a transmit mode; and a power supply to provide operator power to said interface.
a multi pin connector to interconnect said interface to said radio;
a port select circuit including relay means operable in response to an input signal to selectively couple said interface to one of said ports to which means to receive or transmit data and/or voice information is connected;
two-to-four wire converter to connect receive and transmit paths from said connector to said port select circuit;
call and tone detect means responsive to a receive message from said radio to cause said interface to assume a receive transmission mode;
logic means operatively connected to said call and tone detect means to interegate said receive message and to instruct said port select circuit to connect said interface to an appropriate one of said means to receive or transmit voice and data information depending on said receive message;
circuit means responsive to an audio signal from said means to receive and transmit voice and data information to set said radio into a transmit mode; and a power supply to provide operator power to said interface.
11. The interface of claims 1, 5 or 10 further including circuit means to adjust the level of transmit and receive signals.
12. The interface of claims 1, 5 or 10 wherein said con-verter means includes telephone line simulator means to provide load detection, DC loop current and AC ring voltage.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 613824 CA1310066C (en) | 1989-09-28 | 1989-09-28 | Mobile radio interface |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 613824 CA1310066C (en) | 1989-09-28 | 1989-09-28 | Mobile radio interface |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1310066C true CA1310066C (en) | 1992-11-10 |
Family
ID=4140735
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 613824 Expired - Fee Related CA1310066C (en) | 1989-09-28 | 1989-09-28 | Mobile radio interface |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1310066C (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19610777A1 (en) * | 1996-03-19 | 1997-09-25 | Deutsche Telephonwerk Kabel | Data transmission in the voice channel of DECT systems |
-
1989
- 1989-09-28 CA CA 613824 patent/CA1310066C/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19610777A1 (en) * | 1996-03-19 | 1997-09-25 | Deutsche Telephonwerk Kabel | Data transmission in the voice channel of DECT systems |
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| MKLA | Lapsed |