CA1337573E - Device to Provide an Individual Telephone Number for a Facsimile Terminal on a Shared Telephone Line Based on Coded Ringing - Google Patents
Device to Provide an Individual Telephone Number for a Facsimile Terminal on a Shared Telephone Line Based on Coded RingingInfo
- Publication number
- CA1337573E CA1337573E CA0616948A CA616948A CA1337573E CA 1337573 E CA1337573 E CA 1337573E CA 0616948 A CA0616948 A CA 0616948A CA 616948 A CA616948 A CA 616948A CA 1337573 E CA1337573 E CA 1337573E
- Authority
- CA
- Canada
- Prior art keywords
- telefacsimile
- telephone
- terminal
- telephone line
- coil
- 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
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
- H04N1/32—Circuits or arrangements for control or supervision between transmitter and receiver or between image input and image output device, e.g. between a still-image camera and its memory or between a still-image camera and a printer device
- H04N1/327—Initiating, continuing or ending a single-mode communication; Handshaking therefor
- H04N1/32704—Establishing a communication with one of a facsimile and another telecommunication apparatus sharing a single line
- H04N1/32706—Type of the other apparatus
- H04N1/32708—Telephone
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M1/00—Substation equipment, e.g. for use by subscribers
- H04M1/82—Line monitoring circuits for call progress or status discrimination
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M11/00—Telephonic communication systems specially adapted for combination with other electrical systems
- H04M11/06—Simultaneous speech and data transmission, e.g. telegraphic transmission over the same conductors
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
- H04N1/32—Circuits or arrangements for control or supervision between transmitter and receiver or between image input and image output device, e.g. between a still-image camera and its memory or between a still-image camera and a printer device
- H04N1/327—Initiating, continuing or ending a single-mode communication; Handshaking therefor
- H04N1/32704—Establishing a communication with one of a facsimile and another telecommunication apparatus sharing a single line
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
- H04N1/32—Circuits or arrangements for control or supervision between transmitter and receiver or between image input and image output device, e.g. between a still-image camera and its memory or between a still-image camera and a printer device
- H04N1/327—Initiating, continuing or ending a single-mode communication; Handshaking therefor
- H04N1/32704—Establishing a communication with one of a facsimile and another telecommunication apparatus sharing a single line
- H04N1/32715—Detecting
- H04N1/32726—Detecting signals other than facsimile protocol signals, e.g. DTMF signals
Abstract
An electronic device for coupling a telefacsimile terminal (i.e. a fax machine) to a telephone line on receipt of a coded telephone number ringing signal. A code detector means detects a coded telephone number ringing signal and, on detection of the same, activates switch means to couple the telephone line to the telefacsimile terminal. When the device instead receives an uncoded telephone number ringing signal the telephone line is coupled only to any telephone instrument on the line to cause ringing of the instrument in the usual manner and the telefacsimile terminal is uncoupled from the telephone line.
Description
-1 33~573 The invention relates to a device for coupling either a telephone instrument or a telefacsimile terminal to a single telephone line. More specifically, the invention relates to such a device wherein a coded signal couples the telephone line to the telefacsimile terminal, and an uncoded signal couples the telephone line to the telephone instrument.
Devices exist which allege to permit facsimile terminals to share a telephone line with other uses, for example, with a telephone instrument. However, these devices do not provide a second telephone number.
Typically, the prior art devices depend on the presence of a "fax tone" which is actualiy a "calling non-speech device"
tone and is missing in a substantial number of facsimile terminals presently in use. Other devices rely on delay, and assume that a human will pick up a telephone receiver after three to five rings, and, after a delay, switch to the telefacsimile terminal.
There are, however, systems which do share a single line between at least two telephone devices such as, for example, a telephone instrument and a telefacsimile terminal. Two such systems are described in ~.S. Patent 4,578,534, Shelley, March 25, 1986 and 4,825,465, Ryan, April 25, 1989.
In the '534 patent, the non-dedicated telephone line 20 can be connected either to a data set 10 or a tele-phone instrument 40 through contacts a, b and c of relay 61.
When a computer is to access the data set 10, it sends a single ring burst. On receipt of this single ring burst, contacts a and b remain connected and the system dials the telephone number of the computer. When an external party wishes to reach the telephone instrument, the telephone number of the instrument is dialed. On the second ring burst, contact b will mate with contact c by action of the relay 61 so that the telephone instrument is connected to the telephone line 20. The system does not use two tele-phone numbers, including the coded telephone number, as in the inventive system.
In the '465 patent, a controller 10 consists of two parallel circuits 26 and 28 (see Figure 2 of the Patent). Circuit 26 comprises a relay Ll having coils 30 and 32 and operating contacts 38 and 40. Circuit 28 com-prises a relay L2 having coils 34 and 36 which operate contacts 42 and 44. Circuit 26 connects a telephone line to a device 12 (a PBX), while circuit 28 connects the same telephone line to a device 14 (a telefax machine). When one of these devices is in the off hook condition, current will flow thrugh the coils of its relay to thereby disconnect the other device from the telephone line so that only one device is connected to the telephone line at a time. For example, if the telephone receiver of the PBX is lifted off the hook, current will flow through coils 30 and 32 so that contacts 38 and 40 will disconnect. Thus, only the telephone device will be connected to the line 18.
In both of the patented devices, only a single telephone number is used to access either the telephone instrument or a second telephone device. Thus, the feature of automatically being connected to the telefax or the receiver as a function of the telephone number dialed is not included in, nor would it be obvious from, the teachings of the selected references.
It is therefore an object of the invention to provide a device for the above-stated-purpose whic~, over-comes the disadvantages of prior art devices.
It is a further object of the invention which is based on a coded ringing signal.
In accordance with the invention there is provided a device for coupling either a telephone instrument, on receipt of an uncoded telephone number ringing signal, or a telefacsimile terminal, on receipt of a coded telephone number ringing signal, to a telephone line, comprising:
first coupling means for coupling said telephone line to said telephone instrument;
switch means which, when activated, decouple said first coupling means and couple said telephone line to said telefacsimile terminal;
code detector means for detecting said coded telephone number ringing signal and, on detection of said coded telephone number ringing signal, activating said switch means;
wherein, when said device receives said uncoded telephone number ringing signal, said first coupling means couples said telephone line to said telephone instrument to cause ringing of said telephone instrument; and when said device receives said coded telephone number ringing signal, said first coupling means is decoupled and said telephone line is coupled to said telefacsimile terminal;
whereby, when said telephone line is coupled to said telephone instrument, said telefacsimile terminal is isolated from said telephone line; and ` -when said telephone line is coupled to said tele-facsimile terminal, said telephone instrument is isolated from said telephone line.
The invention will be better understood by an examination of the following description, together with the accompanying drawing which illustrates a preferred embodi-ment of the invention.
Referring to the drawing, an input telephone line 1 is connectable either, via telephone instrument line 3 to a telephone instrument 5, or, via telefacsimile terminal line 7 to a telefacsimile terminal 9. A rectifier bridge 11, comprising diodes Dl, D2, D3 and D4, is connected across the line 3 and presents a rectified signal to the telephone instrument on receipt of an uncoded telephone number.
Relay 13 comprises movable switches 15 and coils 17 and 19. When current runs through either coil 17 or coil 19, the switches 15 will move to their closed position.
Detector 21 detects a coded telephone number and, on detection of the coded telephone number, causes current to flow through the coil 19.
In operation, the telephone circuit of line 3 used for normal telephone operation is not interrupted. The device is attached to the circuit in parallel and the fac-simile terminal is attached to the device. The device requires no external power other than that provided by the telephone line, and it does not require a battery.
In the idle condition,~ there is no alternating voltage on the line, and therefore the ringing detector circuit 21 is isolated by capacitor 23 and is not activated.
The rectifier bridge extends the normal supervisory voltage to the facsimile terminal so that the placing of a call from the facsimile terminal can be detected.
When a standard telephone ringing signal is detected, the device rectifies the alternating current ring-ing signal of the telephone number to the facsimile terminal so that only direct current reaches it, and therefore the ringing detector of the fax terminal is not activated, but the called telephone instrument rings in its normal manner.
If a call is placed from the telefacsimile terminal, to send out a telefacsimile signal, current flows in coil 17 so that contacts 15 short out the rectifier bridge 11. Accordingly, the telephone line 1 is connected directly to line 7 of the telefacsimile terminal 9 except for the small resistance of the coil Kl. When the tele-facsimile terminal completes its transmission, coil 17 releases some 75 milliseconds later and the device returns to its idle condition.
The ringing detector 21 is set to detect the presence of 40 to 130 volts alternating current at approxi-mately 20 Hz. If, and only if, ringing is present for, for example, more than 0.75 seconds but less than 1.5 seconds, ringing detector 21 sends a current through coil 2 so that once again switch elements 15 of the relay 13 are closed.
In the above example, with a normal telephone ring of 2 seconds duration and 4 seconds pause between rings, the ringing detector 21 does not operate, i.e., it does not provide a current to the coil 19.
However, with a coded telephone number, the first burst of a "coded" ring is 1 second, for example, followed by one-half second of silence, followed by a second burst of 1 second. Therefore, during the silent period, current is provided to coil 19 so that the second burst is applied to the facsimile terminal causing it to answer. The connection will then be held by the direct line current flowing in coil 19 until the call is cleared.
With the device, there is provided a separate telephone number for both the telephone instrument and the telefacsimile terminal but utilizing only a single telephone line. Accordingly, the cost of an extra telephone line is avoided.
When the telephone instrument is in operation, the telefacsimile terminal is decoupled from the telephone line.
In the same way, when the telefacsimile terminal is in operation, the telephone instrument is decoupled from the telephone line. Accordingly, the decoupled element is isolated from the telephone line when it is decoupled.
The inventive system is not similar to "party line" ringing, which is no longer practical now that most equipment on premises is provided by the customer himself.
With the novel device, it can be seen that calls to the telephone instrument are automatically separated from calls to the telefacsimile terminal, and calls to the tele-facsimile terminal are automatically separated from calls to the telephone instrument. This is, of course, because two separate telephone numbers are used.
In addition, it is possible to use both a tele-phone instrument and a telefacsimile terminal on the same telephone line without one degrading the performance of the other.
In the above embodiment, Applicant has described a time duration code. It will be obvious to one skilled in the art that a different type of code could be used. In addition, Applicant has described specific time durations.
Obviously, different time durations could be used in a time duration code.
Further, the illustrated embodiment shows two separate coils on a single relay. Obviously, two relays could be used wherein each coil would have a separate set of switches.
Thus, although only a single embodiment has been described, this was for the purpose of illustrating, but not limiting, the invention. Various modifications, which will come readily to the mind of one skilled in the art, are within the scope of the invention as defined in the appended claims.
Devices exist which allege to permit facsimile terminals to share a telephone line with other uses, for example, with a telephone instrument. However, these devices do not provide a second telephone number.
Typically, the prior art devices depend on the presence of a "fax tone" which is actualiy a "calling non-speech device"
tone and is missing in a substantial number of facsimile terminals presently in use. Other devices rely on delay, and assume that a human will pick up a telephone receiver after three to five rings, and, after a delay, switch to the telefacsimile terminal.
There are, however, systems which do share a single line between at least two telephone devices such as, for example, a telephone instrument and a telefacsimile terminal. Two such systems are described in ~.S. Patent 4,578,534, Shelley, March 25, 1986 and 4,825,465, Ryan, April 25, 1989.
In the '534 patent, the non-dedicated telephone line 20 can be connected either to a data set 10 or a tele-phone instrument 40 through contacts a, b and c of relay 61.
When a computer is to access the data set 10, it sends a single ring burst. On receipt of this single ring burst, contacts a and b remain connected and the system dials the telephone number of the computer. When an external party wishes to reach the telephone instrument, the telephone number of the instrument is dialed. On the second ring burst, contact b will mate with contact c by action of the relay 61 so that the telephone instrument is connected to the telephone line 20. The system does not use two tele-phone numbers, including the coded telephone number, as in the inventive system.
In the '465 patent, a controller 10 consists of two parallel circuits 26 and 28 (see Figure 2 of the Patent). Circuit 26 comprises a relay Ll having coils 30 and 32 and operating contacts 38 and 40. Circuit 28 com-prises a relay L2 having coils 34 and 36 which operate contacts 42 and 44. Circuit 26 connects a telephone line to a device 12 (a PBX), while circuit 28 connects the same telephone line to a device 14 (a telefax machine). When one of these devices is in the off hook condition, current will flow thrugh the coils of its relay to thereby disconnect the other device from the telephone line so that only one device is connected to the telephone line at a time. For example, if the telephone receiver of the PBX is lifted off the hook, current will flow through coils 30 and 32 so that contacts 38 and 40 will disconnect. Thus, only the telephone device will be connected to the line 18.
In both of the patented devices, only a single telephone number is used to access either the telephone instrument or a second telephone device. Thus, the feature of automatically being connected to the telefax or the receiver as a function of the telephone number dialed is not included in, nor would it be obvious from, the teachings of the selected references.
It is therefore an object of the invention to provide a device for the above-stated-purpose whic~, over-comes the disadvantages of prior art devices.
It is a further object of the invention which is based on a coded ringing signal.
In accordance with the invention there is provided a device for coupling either a telephone instrument, on receipt of an uncoded telephone number ringing signal, or a telefacsimile terminal, on receipt of a coded telephone number ringing signal, to a telephone line, comprising:
first coupling means for coupling said telephone line to said telephone instrument;
switch means which, when activated, decouple said first coupling means and couple said telephone line to said telefacsimile terminal;
code detector means for detecting said coded telephone number ringing signal and, on detection of said coded telephone number ringing signal, activating said switch means;
wherein, when said device receives said uncoded telephone number ringing signal, said first coupling means couples said telephone line to said telephone instrument to cause ringing of said telephone instrument; and when said device receives said coded telephone number ringing signal, said first coupling means is decoupled and said telephone line is coupled to said telefacsimile terminal;
whereby, when said telephone line is coupled to said telephone instrument, said telefacsimile terminal is isolated from said telephone line; and ` -when said telephone line is coupled to said tele-facsimile terminal, said telephone instrument is isolated from said telephone line.
The invention will be better understood by an examination of the following description, together with the accompanying drawing which illustrates a preferred embodi-ment of the invention.
Referring to the drawing, an input telephone line 1 is connectable either, via telephone instrument line 3 to a telephone instrument 5, or, via telefacsimile terminal line 7 to a telefacsimile terminal 9. A rectifier bridge 11, comprising diodes Dl, D2, D3 and D4, is connected across the line 3 and presents a rectified signal to the telephone instrument on receipt of an uncoded telephone number.
Relay 13 comprises movable switches 15 and coils 17 and 19. When current runs through either coil 17 or coil 19, the switches 15 will move to their closed position.
Detector 21 detects a coded telephone number and, on detection of the coded telephone number, causes current to flow through the coil 19.
In operation, the telephone circuit of line 3 used for normal telephone operation is not interrupted. The device is attached to the circuit in parallel and the fac-simile terminal is attached to the device. The device requires no external power other than that provided by the telephone line, and it does not require a battery.
In the idle condition,~ there is no alternating voltage on the line, and therefore the ringing detector circuit 21 is isolated by capacitor 23 and is not activated.
The rectifier bridge extends the normal supervisory voltage to the facsimile terminal so that the placing of a call from the facsimile terminal can be detected.
When a standard telephone ringing signal is detected, the device rectifies the alternating current ring-ing signal of the telephone number to the facsimile terminal so that only direct current reaches it, and therefore the ringing detector of the fax terminal is not activated, but the called telephone instrument rings in its normal manner.
If a call is placed from the telefacsimile terminal, to send out a telefacsimile signal, current flows in coil 17 so that contacts 15 short out the rectifier bridge 11. Accordingly, the telephone line 1 is connected directly to line 7 of the telefacsimile terminal 9 except for the small resistance of the coil Kl. When the tele-facsimile terminal completes its transmission, coil 17 releases some 75 milliseconds later and the device returns to its idle condition.
The ringing detector 21 is set to detect the presence of 40 to 130 volts alternating current at approxi-mately 20 Hz. If, and only if, ringing is present for, for example, more than 0.75 seconds but less than 1.5 seconds, ringing detector 21 sends a current through coil 2 so that once again switch elements 15 of the relay 13 are closed.
In the above example, with a normal telephone ring of 2 seconds duration and 4 seconds pause between rings, the ringing detector 21 does not operate, i.e., it does not provide a current to the coil 19.
However, with a coded telephone number, the first burst of a "coded" ring is 1 second, for example, followed by one-half second of silence, followed by a second burst of 1 second. Therefore, during the silent period, current is provided to coil 19 so that the second burst is applied to the facsimile terminal causing it to answer. The connection will then be held by the direct line current flowing in coil 19 until the call is cleared.
With the device, there is provided a separate telephone number for both the telephone instrument and the telefacsimile terminal but utilizing only a single telephone line. Accordingly, the cost of an extra telephone line is avoided.
When the telephone instrument is in operation, the telefacsimile terminal is decoupled from the telephone line.
In the same way, when the telefacsimile terminal is in operation, the telephone instrument is decoupled from the telephone line. Accordingly, the decoupled element is isolated from the telephone line when it is decoupled.
The inventive system is not similar to "party line" ringing, which is no longer practical now that most equipment on premises is provided by the customer himself.
With the novel device, it can be seen that calls to the telephone instrument are automatically separated from calls to the telefacsimile terminal, and calls to the tele-facsimile terminal are automatically separated from calls to the telephone instrument. This is, of course, because two separate telephone numbers are used.
In addition, it is possible to use both a tele-phone instrument and a telefacsimile terminal on the same telephone line without one degrading the performance of the other.
In the above embodiment, Applicant has described a time duration code. It will be obvious to one skilled in the art that a different type of code could be used. In addition, Applicant has described specific time durations.
Obviously, different time durations could be used in a time duration code.
Further, the illustrated embodiment shows two separate coils on a single relay. Obviously, two relays could be used wherein each coil would have a separate set of switches.
Thus, although only a single embodiment has been described, this was for the purpose of illustrating, but not limiting, the invention. Various modifications, which will come readily to the mind of one skilled in the art, are within the scope of the invention as defined in the appended claims.
Claims (9)
1. A device for coupling either a telephone instrument, on receipt of an uncoded telephone number ringing signal, or a telefacsimile terminal, on receipt of a coded telephone number ringing signal, to a telephone line, comprising:
switch means which, when activated couples said telephone line to said telefacsimile terminal;
code detector means for detecting said coded telephone number ringing signal and, on detection of said coded telephone number ringing signal, activating said switch means;
wherein, when said device receive said uncoded telephone number ringing sinal, said telephone line is coupled to said telephone instrument to cause ringing of said telephone instrument; and when said device receives said coded telephone number ringing signal, said telephone line is coupled to said telefacsimile terminal;
whereby, when said telephone line is coupled to said telephone instrument, said telefacsimile terminal is isolated from said telephone line.
switch means which, when activated couples said telephone line to said telefacsimile terminal;
code detector means for detecting said coded telephone number ringing signal and, on detection of said coded telephone number ringing signal, activating said switch means;
wherein, when said device receive said uncoded telephone number ringing sinal, said telephone line is coupled to said telephone instrument to cause ringing of said telephone instrument; and when said device receives said coded telephone number ringing signal, said telephone line is coupled to said telefacsimile terminal;
whereby, when said telephone line is coupled to said telephone instrument, said telefacsimile terminal is isolated from said telephone line.
2. A device as defined in claim 1 wherein, when a call is placed from said telefacsimile terminal, a second means activates said switch means;
whereby, said telephone line is coupled to said telefacsimile terminal.
whereby, said telephone line is coupled to said telefacsimile terminal.
3. A device as defined in claim 2 wherein said switch means comprises a rectifier bridge to isolate said telefacsimile terminal from said telephone line until said switch means is activated, a relay having a coil means and switching elements;
wherein, when current flows through said coil means of said relay, said switching elements are activated to short out said rectifier bridge and provide direct connection between said telephone line and said telefacsimile terminal.
wherein, when current flows through said coil means of said relay, said switching elements are activated to short out said rectifier bridge and provide direct connection between said telephone line and said telefacsimile terminal.
4. A device as defined in claim 3 wherein said coil means is disposed in a conductive connection between said telefacsimile terminal and said telephone line;
whereby, when a number is dialled on said telefacsimile terminal to transmit a telefacsimile message, current flows through said coil means to activate said switching elements.
whereby, when a number is dialled on said telefacsimile terminal to transmit a telefacsimile message, current flows through said coil means to activate said switching elements.
5. A device as defined in claim 4 wherein the output of said code detector means is connected to said coil means to provide current when said coded signal is detected to thereby activate said switching elements and to connect said telephone line to said telefacsimile terminal.
6. A device as defined in claim 5 wherein said code detector means detects a ringing signal of duration greater than a first predetermined duration and less than a second predetermined duration.
7. A device as defined in claim 3 wherein said coil means comprises a first coil and a second coil;
said first coil being disposed in a conductive connector between said telefacsimile terminal and said telephone line;
whereby, when a number is dialled on said telefacsimile terminal to transmit a telefacsimile message, current flows through said coil means to activate said switching elements.
said first coil being disposed in a conductive connector between said telefacsimile terminal and said telephone line;
whereby, when a number is dialled on said telefacsimile terminal to transmit a telefacsimile message, current flows through said coil means to activate said switching elements.
8. A device as defined in claim 7 wherein the output of said code detector means is connected to said second coil to provide current when said coded telephone number is detected.
9. A device as defined in claim 8 wherein said code detector means detects a ringing signal of duration greater than a first predetermined duration and less than a second predetermined duration.
.
.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA0616948A CA1337573E (en) | 1989-09-28 | 1994-12-07 | Device to Provide an Individual Telephone Number for a Facsimile Terminal on a Shared Telephone Line Based on Coded Ringing |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000613902A CA1315429C (en) | 1989-09-28 | 1989-09-28 | Device to provide an individual telephone number for a facsimile terminal on a shared telephone line based on coded ringing |
| CA0616948A CA1337573E (en) | 1989-09-28 | 1994-12-07 | Device to Provide an Individual Telephone Number for a Facsimile Terminal on a Shared Telephone Line Based on Coded Ringing |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000613902A Division CA1315429C (en) | 1989-09-28 | 1989-09-28 | Device to provide an individual telephone number for a facsimile terminal on a shared telephone line based on coded ringing |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1337573E true CA1337573E (en) | 1995-11-14 |
Family
ID=4140745
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000613902A Expired - Lifetime CA1315429C (en) | 1989-09-28 | 1989-09-28 | Device to provide an individual telephone number for a facsimile terminal on a shared telephone line based on coded ringing |
| CA0616948A Expired - Fee Related CA1337573E (en) | 1989-09-28 | 1994-12-07 | Device to Provide an Individual Telephone Number for a Facsimile Terminal on a Shared Telephone Line Based on Coded Ringing |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000613902A Expired - Lifetime CA1315429C (en) | 1989-09-28 | 1989-09-28 | Device to provide an individual telephone number for a facsimile terminal on a shared telephone line based on coded ringing |
Country Status (1)
| Country | Link |
|---|---|
| CA (2) | CA1315429C (en) |
-
1989
- 1989-09-28 CA CA000613902A patent/CA1315429C/en not_active Expired - Lifetime
-
1994
- 1994-12-07 CA CA0616948A patent/CA1337573E/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CA1315429C (en) | 1993-03-30 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| NARE | Reissued | ||
| MKLA | Lapsed |