CA1159540A - Digital concentrator for use with a digital telephone office - Google Patents
Digital concentrator for use with a digital telephone officeInfo
- Publication number
- CA1159540A CA1159540A CA000366696A CA366696A CA1159540A CA 1159540 A CA1159540 A CA 1159540A CA 000366696 A CA000366696 A CA 000366696A CA 366696 A CA366696 A CA 366696A CA 1159540 A CA1159540 A CA 1159540A
- Authority
- CA
- Canada
- Prior art keywords
- line
- digital
- operated
- response
- circuit
- 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
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q11/00—Selecting arrangements for multiplex systems
- H04Q11/04—Selecting arrangements for multiplex systems for time-division multiplexing
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- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Sub-Exchange Stations And Push- Button Telephones (AREA)
- Interface Circuits In Exchanges (AREA)
Abstract
TITLE
DIGITAL CONCENTRATOR FOR USE WITH A
DIGITAL TELEPHONE OFFICE
ABSTRACT OF THE DISCLOSURE
Signals from line circuits requesting service are transferred to a T1 channel via a Pulse Amplitude Modulated (PAM) bus. The number of line circuits which can be served by a T1 line is not limited by the capacity of the T1 line since the probability of all line circuits requesting service at the same time is extremely low. A processing unit detects requests for service and assigns them a slot in a memory which defines the scanning sequence for in-sertion of line circuit signal in the T1 channel.
DIGITAL CONCENTRATOR FOR USE WITH A
DIGITAL TELEPHONE OFFICE
ABSTRACT OF THE DISCLOSURE
Signals from line circuits requesting service are transferred to a T1 channel via a Pulse Amplitude Modulated (PAM) bus. The number of line circuits which can be served by a T1 line is not limited by the capacity of the T1 line since the probability of all line circuits requesting service at the same time is extremely low. A processing unit detects requests for service and assigns them a slot in a memory which defines the scanning sequence for in-sertion of line circuit signal in the T1 channel.
Description
.~
TITLE
DIGITAL CONCENTRATOR FOR ~SE WITH A
DIGITAL TEL~PHONE OFFICE
BACKGROUND OF THE INVENTION
.__ (l~_Field of the Invention The present invention relates to digital telephone switching and more particularly to a digital concentrator for use with a digital telephone office.
The digital concentrator allows the number of sub-scriber stations connected to a Tl line to exceedthe capacity of the Tl line based on the probability of occurrence of simultaneous requests for service~
Remote subscriber stations are thus provided with the full range of customer features associated with a digital telephone office. Thus an economical means is provided for connecting remote subscriber stations to a class 5 telephone office.
TITLE
DIGITAL CONCENTRATOR FOR ~SE WITH A
DIGITAL TEL~PHONE OFFICE
BACKGROUND OF THE INVENTION
.__ (l~_Field of the Invention The present invention relates to digital telephone switching and more particularly to a digital concentrator for use with a digital telephone office.
The digital concentrator allows the number of sub-scriber stations connected to a Tl line to exceedthe capacity of the Tl line based on the probability of occurrence of simultaneous requests for service~
Remote subscriber stations are thus provided with the full range of customer features associated with a digital telephone office. Thus an economical means is provided for connecting remote subscriber stations to a class 5 telephone office.
(2)_ Description of the Prior Art Concentration systems are old and well known. Typically they require a concentrator located near the subscriber stations and an expander located in a central office. Such concentrators and expanders are of an analog nature and require one appearance on the output of the expander for each appearance on the input of the concentrator. Thus the connection between these subscriber stations and the telephone ' , ,, ' , : : - ~ , . , ,; ~ ", , 5 ~
office are minimized, but such an arrangement requires the use of an expansion stage. Further/ such analog concentration systems are not adaptable to digital telephone offices unless the analog signals from the output of the expansion stage are converted to digital format for use by the digital telephone office.
Accordingly, it is an object of the present invention to provide a digital concentrator which can be connected directly to a digital telephone office without the use of an expansion stage or an analog to digital interface.
SUMMAR~ OF THE INVENTION
The present invention provides for digital concentration of connections between remote subscriber stations and a Tl channel connected to a digital telephone office. Thus it extends the full range of features of a digital telephone office to rural subscribers by allowing the number of subscriber stations, connected to a Tl line, to exceed the capacity of the Tl line. Based on probability of occurrence of simultaneous requests for service a 4 to 1 con-centration stage is practical. Thus 96 subscriber stations can be connected to one Tl line via the digital concentrator.
The digital concentrator includes a Pulse Amplitude Modulated (PAM~ bus connected to a plurality of line circuits via associated sample and hold circuits, filter circuits and hybrid circuits. This PAM bus is further connected to a non-linear A/D-D/A converter which converts the PAM signals to Pulse Code Modulated (PCM) signals. A digital trunk interface is connected to the A/D-D/A converter and provides transmission of the PCM signals to an associated digital telephone office. Each sample and hold circuit samples the analog output of an associated filter and extends the sample through it so that the A/D converter has sufficient real time to make the conversion. An analog gate is enabled by a decoder which decoded data from a :
memory which was loaded by a processing unit. The decoder operates to selectively enable the connection of the various line circuits to the digital trunk interface.
The line circuits are connected to the PAM
bus according to the sequence of addresses read from the memory. When a subscriber station goes off-hook, its associated line circuit extends a signal to the processing unit which detects this request for service and communicates the line circui~ number to the tele-phone office via the digital trunk interface. The telephone office responds by transmitting the Tl line channel number to be assigned to this line circuit and the processing unit loads the designated memory slot with the line circuit address. The memory se-quentially displays the line circuit addresses which are decoded and used to enable the corresponding line circuit connection to a non-linear A/D and D/A con-verter which converts them from PAM format to PCM
ormat. These signals are then transferred to the digital trunk interface which inserts them in the Tl channel data stream and transmits them to an as-sociated digital telephone office.
When the next line circuit address is read out of the memory the decoder again enables signals from the associated subscriber station to be gated to the A/D-D/A converterO Thus each subscriber station which is busy is given a time slot in the sequence defined by the position of its address in the memory during which its signals are transmitted to the tele-phone office. A clock circuit is used to control the rate at which addresses are read out of the memory and thus also determines the duration of the time period during which each subscriber station is enabled through the PAM bus. The digital trunk interface thus inserts the PCM signals associated with the time slot for each subscriber station in a predetermined position in a Tl line. A Tl line is a repetitive .
transmission of 193 bits during each 125 microseconds.
These 193 bits include a framing bit and 24 signals represented by an 8-bit code of each signal.
Thus 96 subscriber stations are connected to a digital telephone office via a single Tl line and are provided access to a channel on a request for service basis.
DESCRIPTION OF T~E DRAWING
The single figure of the accompanying drawing is a block diagram of a digital concen'crator for use with a digital telephone office in accordance with the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the accompanying drawing, the diyital concentrator of the present invention is shown connected between a plurality of subscriber stations and a digital telephone office. Line circuits are shown connected between associated subscriber stations and their associated sample and hold circuits (15-17) which are connected to analog gate circuits 23, 25, 27. The line circuits are further connected to analog gate circuits 24, 26, 28. Non-linear A/D-D/A
converter 30 is shown connected between PAM bus 29 and digital trunk 40. Data link 50 is connected be-tween digital trunk 40 and unipolar/bipolar converter60 which is connected to an associated digital tele-phone office. Processing unit 100 i~ shown connected to data link 50 and the line circuits. Line circuits, sample and hold circuits, analog gate circuits, A/D-D/A
converters, digital trunks and unipolar/bipolar con-verters are well known in the field of digital tele-phone offices. Data link 50 is a bit stream merging circuit. Such circuits are old and well known and have long been used to merge supervisory data into the supervisory channels of a Tl frame, i.e. the eighth bit of each channel in every 6th frame. Data link 50 can also be a novel circuit which is disclosed in our copending application SN 366,695-6 titled, '~^
. 1 ~ `
.
, . .
Digital Satellita Telephone Office, which was filed on December 12, 1980. Processing units are also old and well known and any suitable compute~, mini-computer or microprocessor can be used.
Processing unit 100 initially detects a request for service from an off-hook subscriber station via its associated line circuit, particularly the make contacts of relay 1. Processing unit 100 then con~unicates the identity of the off-hook subscriber station to an associated telephone office via data link 50 which sequentially inserts each bit of this communication sequentially into the framing pattern of the Tl line data stream generated by digital trunk 40. Each Tl line data frame includes 193 bits which comprise 24 channels of 8-bits each plus a framing bit. Since the terminal framing bit is only used in every odd numbered frame, the framing bit position is available for supervisory signaling in every even numbered frame and data link 50 inserts the bits transmitted between processing unit 100 and the digital telephone office in that spare framing bit position.
The telephone office responds by transmitting the Tl channel number to be assiged to the off-hook subscribar station. In this manner, the digital tele-phone office knows which subscriber sta~ion is trans-mitting in which Tl channel and thus there is no need for an expansion stage to provide an appearance for each subscriber station at the telephone office.
Processing unit 100 then loads memory 22 witb the address of the off-hook line circuit to be connected ~o PAM bus 29. Clock 20 then causes the addresses to be read out of memory 21 sequentially and decoder 22 operates to generate an individual enable signal for each sequential address decoded from memory 21. Analog gating circuits 23 through 28 thus becoma enabled when their connection to decoder 22 is enabled.
.
For example, when the subscriber station connected to line equipment 11 goes off-hook it ex-tends a loop signal to line circuit 11 which converts it to a 4-wire signal via hybrid 2, amplifies it via S amplifier 3 and filters it with filter 5. This signal i5 then sampled and held by sample and hold circuit 15 which transfers it as sampled to gate circuit 23.
However gate circuit 23 is not enabled until clock cireuit 20 causes the address associated with line equipment 11 to be read out of memory 21, and decoded by decoder 22, thus enabling gate circuit 23. Pro-cessing unit 100 previously loaded the address of the off-hook line circuit in the memory slot identified by the telephone office. Upon being enabled gate circuit 23 transfers the signal from line equipment 11 to PAM bus 29. The signal from line circuit 11 thus remains extended via gate circuit 23 and PAM
bus 29 to A/D-D/A converter 30 as long as its asso-ciated address is decoded by decoder 22.
When the clock circuit 20 generates the next clock pulse, memory circuit 21 displays the next sequential line circuit address which is decoded by decoder 22 and thus causes the associated gate circuit to become enabled while gate circuit 23 is disabled.
Thus the signal lead from line circuit 11 will no longer be extended tG A/D-D/A converter 30 but the signal lead from the next sequentially enabled line eircuit will be extended via an associated enabled gate eircuit and PAM bus connection 29 to A/D-D/A
eonverter 30.
In this manner each connected subscriber s~ation generating a request for serviee is given a time slot as defined by the duration of the clock pulses generated by clock circuit 20 during which they have access to A/D-D/A eonverter 30 via an asso-ciated gate circuit and PAM bus connection 29. A/D-D/A
eonverter 30 then eonverts the Pulse Amplitude Modula-tion (PAM) signals received from PAM bus connection , l~ -7~
29 to Pulse Code Modulation (PCM) signals which are extended to digital trunk 40. Digital trunk 40 then inserts each 8-bit PCM signal from A/D-D/A converter 30 into one of the 24 8-bit channels defined on the Tl line. Therefore clock circuit 20 can enable a maximum of 24 subscribers stations during each Tl line time period. Data link 50 transmits these signals to unipolar/bipolar converter 60 which converts them from the unipolar ~ormat used in the digital concen-trator to the bipolar format used for transmissionbetween telephone offlces.
Similarly the associated digital telephone office can transmit PCM signals to the digital con-centrator which will be received by the digital trunk interface. A/D-D/A converter 30 then converts these PCM signals into PAM signals and applies them to PAM
bus 29. Again PAM bus 29 must be enabled in order to transmit signals and therefore when clock circuit 20 causes memory 21 to display a line circuit address decoder 22 enables the decoded analog gate circuit (e.g. 24, 26, or 28), which transmits these signals to the connected line circuit and consequently to the connected subscriber station.
The digital concentrator makes this con-nection economical since it allows the number ofsubscriber stations connected to a Tl channel to e~-ceed the capacity of the Tl channel based on the low probability of simultaneous requests for service.
Rural tel~phone subscribers are thus provided with full feature telephone service through use of a digital concentrator connected to a remote digital telephone office.
It will be obvious to those skilled in the art that numerous modifications of the present invention can be made without departing from the spirit of the invention which shall be limited only by the scope of the claims appended hereto.
P~j ~.
~.
.
office are minimized, but such an arrangement requires the use of an expansion stage. Further/ such analog concentration systems are not adaptable to digital telephone offices unless the analog signals from the output of the expansion stage are converted to digital format for use by the digital telephone office.
Accordingly, it is an object of the present invention to provide a digital concentrator which can be connected directly to a digital telephone office without the use of an expansion stage or an analog to digital interface.
SUMMAR~ OF THE INVENTION
The present invention provides for digital concentration of connections between remote subscriber stations and a Tl channel connected to a digital telephone office. Thus it extends the full range of features of a digital telephone office to rural subscribers by allowing the number of subscriber stations, connected to a Tl line, to exceed the capacity of the Tl line. Based on probability of occurrence of simultaneous requests for service a 4 to 1 con-centration stage is practical. Thus 96 subscriber stations can be connected to one Tl line via the digital concentrator.
The digital concentrator includes a Pulse Amplitude Modulated (PAM~ bus connected to a plurality of line circuits via associated sample and hold circuits, filter circuits and hybrid circuits. This PAM bus is further connected to a non-linear A/D-D/A converter which converts the PAM signals to Pulse Code Modulated (PCM) signals. A digital trunk interface is connected to the A/D-D/A converter and provides transmission of the PCM signals to an associated digital telephone office. Each sample and hold circuit samples the analog output of an associated filter and extends the sample through it so that the A/D converter has sufficient real time to make the conversion. An analog gate is enabled by a decoder which decoded data from a :
memory which was loaded by a processing unit. The decoder operates to selectively enable the connection of the various line circuits to the digital trunk interface.
The line circuits are connected to the PAM
bus according to the sequence of addresses read from the memory. When a subscriber station goes off-hook, its associated line circuit extends a signal to the processing unit which detects this request for service and communicates the line circui~ number to the tele-phone office via the digital trunk interface. The telephone office responds by transmitting the Tl line channel number to be assigned to this line circuit and the processing unit loads the designated memory slot with the line circuit address. The memory se-quentially displays the line circuit addresses which are decoded and used to enable the corresponding line circuit connection to a non-linear A/D and D/A con-verter which converts them from PAM format to PCM
ormat. These signals are then transferred to the digital trunk interface which inserts them in the Tl channel data stream and transmits them to an as-sociated digital telephone office.
When the next line circuit address is read out of the memory the decoder again enables signals from the associated subscriber station to be gated to the A/D-D/A converterO Thus each subscriber station which is busy is given a time slot in the sequence defined by the position of its address in the memory during which its signals are transmitted to the tele-phone office. A clock circuit is used to control the rate at which addresses are read out of the memory and thus also determines the duration of the time period during which each subscriber station is enabled through the PAM bus. The digital trunk interface thus inserts the PCM signals associated with the time slot for each subscriber station in a predetermined position in a Tl line. A Tl line is a repetitive .
transmission of 193 bits during each 125 microseconds.
These 193 bits include a framing bit and 24 signals represented by an 8-bit code of each signal.
Thus 96 subscriber stations are connected to a digital telephone office via a single Tl line and are provided access to a channel on a request for service basis.
DESCRIPTION OF T~E DRAWING
The single figure of the accompanying drawing is a block diagram of a digital concen'crator for use with a digital telephone office in accordance with the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the accompanying drawing, the diyital concentrator of the present invention is shown connected between a plurality of subscriber stations and a digital telephone office. Line circuits are shown connected between associated subscriber stations and their associated sample and hold circuits (15-17) which are connected to analog gate circuits 23, 25, 27. The line circuits are further connected to analog gate circuits 24, 26, 28. Non-linear A/D-D/A
converter 30 is shown connected between PAM bus 29 and digital trunk 40. Data link 50 is connected be-tween digital trunk 40 and unipolar/bipolar converter60 which is connected to an associated digital tele-phone office. Processing unit 100 i~ shown connected to data link 50 and the line circuits. Line circuits, sample and hold circuits, analog gate circuits, A/D-D/A
converters, digital trunks and unipolar/bipolar con-verters are well known in the field of digital tele-phone offices. Data link 50 is a bit stream merging circuit. Such circuits are old and well known and have long been used to merge supervisory data into the supervisory channels of a Tl frame, i.e. the eighth bit of each channel in every 6th frame. Data link 50 can also be a novel circuit which is disclosed in our copending application SN 366,695-6 titled, '~^
. 1 ~ `
.
, . .
Digital Satellita Telephone Office, which was filed on December 12, 1980. Processing units are also old and well known and any suitable compute~, mini-computer or microprocessor can be used.
Processing unit 100 initially detects a request for service from an off-hook subscriber station via its associated line circuit, particularly the make contacts of relay 1. Processing unit 100 then con~unicates the identity of the off-hook subscriber station to an associated telephone office via data link 50 which sequentially inserts each bit of this communication sequentially into the framing pattern of the Tl line data stream generated by digital trunk 40. Each Tl line data frame includes 193 bits which comprise 24 channels of 8-bits each plus a framing bit. Since the terminal framing bit is only used in every odd numbered frame, the framing bit position is available for supervisory signaling in every even numbered frame and data link 50 inserts the bits transmitted between processing unit 100 and the digital telephone office in that spare framing bit position.
The telephone office responds by transmitting the Tl channel number to be assiged to the off-hook subscribar station. In this manner, the digital tele-phone office knows which subscriber sta~ion is trans-mitting in which Tl channel and thus there is no need for an expansion stage to provide an appearance for each subscriber station at the telephone office.
Processing unit 100 then loads memory 22 witb the address of the off-hook line circuit to be connected ~o PAM bus 29. Clock 20 then causes the addresses to be read out of memory 21 sequentially and decoder 22 operates to generate an individual enable signal for each sequential address decoded from memory 21. Analog gating circuits 23 through 28 thus becoma enabled when their connection to decoder 22 is enabled.
.
For example, when the subscriber station connected to line equipment 11 goes off-hook it ex-tends a loop signal to line circuit 11 which converts it to a 4-wire signal via hybrid 2, amplifies it via S amplifier 3 and filters it with filter 5. This signal i5 then sampled and held by sample and hold circuit 15 which transfers it as sampled to gate circuit 23.
However gate circuit 23 is not enabled until clock cireuit 20 causes the address associated with line equipment 11 to be read out of memory 21, and decoded by decoder 22, thus enabling gate circuit 23. Pro-cessing unit 100 previously loaded the address of the off-hook line circuit in the memory slot identified by the telephone office. Upon being enabled gate circuit 23 transfers the signal from line equipment 11 to PAM bus 29. The signal from line circuit 11 thus remains extended via gate circuit 23 and PAM
bus 29 to A/D-D/A converter 30 as long as its asso-ciated address is decoded by decoder 22.
When the clock circuit 20 generates the next clock pulse, memory circuit 21 displays the next sequential line circuit address which is decoded by decoder 22 and thus causes the associated gate circuit to become enabled while gate circuit 23 is disabled.
Thus the signal lead from line circuit 11 will no longer be extended tG A/D-D/A converter 30 but the signal lead from the next sequentially enabled line eircuit will be extended via an associated enabled gate eircuit and PAM bus connection 29 to A/D-D/A
eonverter 30.
In this manner each connected subscriber s~ation generating a request for serviee is given a time slot as defined by the duration of the clock pulses generated by clock circuit 20 during which they have access to A/D-D/A eonverter 30 via an asso-ciated gate circuit and PAM bus connection 29. A/D-D/A
eonverter 30 then eonverts the Pulse Amplitude Modula-tion (PAM) signals received from PAM bus connection , l~ -7~
29 to Pulse Code Modulation (PCM) signals which are extended to digital trunk 40. Digital trunk 40 then inserts each 8-bit PCM signal from A/D-D/A converter 30 into one of the 24 8-bit channels defined on the Tl line. Therefore clock circuit 20 can enable a maximum of 24 subscribers stations during each Tl line time period. Data link 50 transmits these signals to unipolar/bipolar converter 60 which converts them from the unipolar ~ormat used in the digital concen-trator to the bipolar format used for transmissionbetween telephone offlces.
Similarly the associated digital telephone office can transmit PCM signals to the digital con-centrator which will be received by the digital trunk interface. A/D-D/A converter 30 then converts these PCM signals into PAM signals and applies them to PAM
bus 29. Again PAM bus 29 must be enabled in order to transmit signals and therefore when clock circuit 20 causes memory 21 to display a line circuit address decoder 22 enables the decoded analog gate circuit (e.g. 24, 26, or 28), which transmits these signals to the connected line circuit and consequently to the connected subscriber station.
The digital concentrator makes this con-nection economical since it allows the number ofsubscriber stations connected to a Tl channel to e~-ceed the capacity of the Tl channel based on the low probability of simultaneous requests for service.
Rural tel~phone subscribers are thus provided with full feature telephone service through use of a digital concentrator connected to a remote digital telephone office.
It will be obvious to those skilled in the art that numerous modifications of the present invention can be made without departing from the spirit of the invention which shall be limited only by the scope of the claims appended hereto.
P~j ~.
~.
.
Claims (6)
1. A digital concentrator including a plurality of line circuits operated to generate line transmit signals, said digital concentrator comprisng:
selection means connected to said line circuits, operated in response to said line transmit signals from each line circuit to generate an asso-ciated periodic enable signal;
a plurality of transmit gating means con-nected to said plurality of line circuits, and to said selection means, each operated in response to a predetermined one of said enable signals to gate the line transmit signal from a connected line circuit for a predetermined time;
conversion means connected to said plurality of transmit gating means operated in response to each of said gated line transmit signals to generate a group of simultaneously occurring digital line trans-mit signals; and a digital trunk interface connected to said conversion means operated in response to each group of simultaneously occurring digital line transmit signals to generate a group of serial digital line transmit signals, and further operated to sequentially concatenate each group of said serial digital line transmit signals, into a first serial data stream.
selection means connected to said line circuits, operated in response to said line transmit signals from each line circuit to generate an asso-ciated periodic enable signal;
a plurality of transmit gating means con-nected to said plurality of line circuits, and to said selection means, each operated in response to a predetermined one of said enable signals to gate the line transmit signal from a connected line circuit for a predetermined time;
conversion means connected to said plurality of transmit gating means operated in response to each of said gated line transmit signals to generate a group of simultaneously occurring digital line trans-mit signals; and a digital trunk interface connected to said conversion means operated in response to each group of simultaneously occurring digital line transmit signals to generate a group of serial digital line transmit signals, and further operated to sequentially concatenate each group of said serial digital line transmit signals, into a first serial data stream.
2. A digital concentrator as claimed in claim 1, wherein said digital concentrator is con-nected to a digital telephone office operated to generate a second serial data stream including a plurality of groups of serial digital line receive signals;
said digital trunk interface further operated in response to said second serial data stream to se-quentially generate a plurality of groups of simulta-neously occurring digital line receive signals;
said conversion means further operated in response to each of said groups of simultaneously occurring digital line receive signals to generate an analog line receive signal; and a plurality of receive gating means con-nected to said plurality of line circuits, said con-version means and said selection means, each operated in response to a predetermined one of said enable signals to gate each of said line receive signals to a predetermined line circuit.
said digital trunk interface further operated in response to said second serial data stream to se-quentially generate a plurality of groups of simulta-neously occurring digital line receive signals;
said conversion means further operated in response to each of said groups of simultaneously occurring digital line receive signals to generate an analog line receive signal; and a plurality of receive gating means con-nected to said plurality of line circuits, said con-version means and said selection means, each operated in response to a predetermined one of said enable signals to gate each of said line receive signals to a predetermined line circuit.
3. A digital concentrator as claimed in claim 2, wherein said selection means comprise:
a processing unit connected to said line circuits and to said digital trunk interface;
a memory connected to said processing unit;
said processing unit operated in response to said line transmit signals from each line circuit to generate a line circuit address signal;
said digital trunk interface further operated in response to said line circuit address signal to insert each bit of said line circuit address signal in a predetermined bit position of said first serial data stream;
said telephone office further operated in response to said line circuit address bits to generate a memory address signal and insert each bit of said memory address signal in a predetermined bit position of said second serial data stream;
said digital trunk interface further operated in response to said memory address bits to retrieve said memory address signal; and said processing unit further operated in response to said retrieved memory address signal to store said line circuit address signal in said memory at a location represented by said retrieved memory address signal.
a processing unit connected to said line circuits and to said digital trunk interface;
a memory connected to said processing unit;
said processing unit operated in response to said line transmit signals from each line circuit to generate a line circuit address signal;
said digital trunk interface further operated in response to said line circuit address signal to insert each bit of said line circuit address signal in a predetermined bit position of said first serial data stream;
said telephone office further operated in response to said line circuit address bits to generate a memory address signal and insert each bit of said memory address signal in a predetermined bit position of said second serial data stream;
said digital trunk interface further operated in response to said memory address bits to retrieve said memory address signal; and said processing unit further operated in response to said retrieved memory address signal to store said line circuit address signal in said memory at a location represented by said retrieved memory address signal.
4. A digital concentrator as claimed in claim 3, wherein said selection means further comprise:
a clock circuit operated to generate periodic clock pulses;
said memory further connected to said clock circuit, operated in response to each successive clock pulse to display the line circuit address contained in each successive memory location; and a decoder connected to said memory operated in response to each of said displayed line circuit addresses to generate said line circuit enable signal.
a clock circuit operated to generate periodic clock pulses;
said memory further connected to said clock circuit, operated in response to each successive clock pulse to display the line circuit address contained in each successive memory location; and a decoder connected to said memory operated in response to each of said displayed line circuit addresses to generate said line circuit enable signal.
5. A digital concentrator as claimed in claim 1, wherein said conversion means comprises an A/D-D/A converter.
6. A digital concentrator as claimed in claim 1, wherein each of said transmit gating means comprises:
a sample and hold circuit connected to an associated line circuit, operated to sample and hold the line transmit signals from the connected line circuit for a predetermined time; and an analog gating circuit, connected to an associated sample and hold circuit, operated in response to said predetermined one of said enable signals to gate the line transmit signal from the connected line circuit to said conversion means.
a sample and hold circuit connected to an associated line circuit, operated to sample and hold the line transmit signals from the connected line circuit for a predetermined time; and an analog gating circuit, connected to an associated sample and hold circuit, operated in response to said predetermined one of said enable signals to gate the line transmit signal from the connected line circuit to said conversion means.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US06/289,954 US4385379A (en) | 1979-12-19 | 1981-08-05 | Digital concentrator for use with a digital telephone office |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US10543679A | 1979-12-19 | 1979-12-19 | |
| US105,436 | 1979-12-19 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1159540A true CA1159540A (en) | 1983-12-27 |
Family
ID=22305841
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000366696A Expired CA1159540A (en) | 1979-12-19 | 1980-12-12 | Digital concentrator for use with a digital telephone office |
Country Status (2)
| Country | Link |
|---|---|
| BE (1) | BE885962A (en) |
| CA (1) | CA1159540A (en) |
-
1980
- 1980-10-31 BE BE2/58836A patent/BE885962A/en not_active IP Right Cessation
- 1980-12-12 CA CA000366696A patent/CA1159540A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| BE885962A (en) | 1981-02-16 |
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