CA1037169A - T.d.m. exchange systems - Google Patents
T.d.m. exchange systemsInfo
- Publication number
- CA1037169A CA1037169A CA178,750A CA178750A CA1037169A CA 1037169 A CA1037169 A CA 1037169A CA 178750 A CA178750 A CA 178750A CA 1037169 A CA1037169 A CA 1037169A
- Authority
- CA
- Canada
- Prior art keywords
- channel
- transmission
- transmitting
- command information
- store
- 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
- H04J—MULTIPLEX COMMUNICATION
- H04J3/00—Time-division multiplex systems
- H04J3/16—Time-division multiplex systems in which the time allocation to individual channels within a transmission cycle is variable, e.g. to accommodate varying complexity of signals, to vary number of channels transmitted
- H04J3/1605—Fixed allocated frame structures
- H04J3/1623—Plesiochronous digital hierarchy [PDH]
- H04J3/1647—Subrate or multislot multiplexing
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J3/00—Time-division multiplex systems
- H04J3/02—Details
- H04J3/12—Arrangements providing for calling or supervisory signals
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L5/00—Arrangements affording multiple use of the transmission path
- H04L5/22—Arrangements affording multiple use of the transmission path using time-division multiplexing
Landscapes
- Engineering & Computer Science (AREA)
- Signal Processing (AREA)
- Computer Networks & Wireless Communication (AREA)
- Time-Division Multiplex Systems (AREA)
- Data Exchanges In Wide-Area Networks (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A t.d.m. exchange system comprising a transmitting and a receiving store for use in the temporary combination of subsidiary channels to form a transmission channel possessing a higher chan-nel capacity than the individual subsidiary channels and for the characterisation of the operating mode on said higher capacity transmission channel. An item of command information formed in said exchange system is recorded, together with an additional criterion, into a storage cell, assigned to an unseized subsidiary channels, of the transmitting store, and is transmitted via a data channel connected to the exchange system. On the reception of a piece of command information in said exchange, at least two equi-distant subsidiary channels are combined to form a higher capacity transmission channel, and the operating mode for the subsequent data transmission is set. On the reception, in said exchange, of a connection clearing signal relating to a connection being con-ducted via a higher capacity transmission channel, said channel is broken up into its constituent subsidiary channels.
A t.d.m. exchange system comprising a transmitting and a receiving store for use in the temporary combination of subsidiary channels to form a transmission channel possessing a higher chan-nel capacity than the individual subsidiary channels and for the characterisation of the operating mode on said higher capacity transmission channel. An item of command information formed in said exchange system is recorded, together with an additional criterion, into a storage cell, assigned to an unseized subsidiary channels, of the transmitting store, and is transmitted via a data channel connected to the exchange system. On the reception of a piece of command information in said exchange, at least two equi-distant subsidiary channels are combined to form a higher capacity transmission channel, and the operating mode for the subsequent data transmission is set. On the reception, in said exchange, of a connection clearing signal relating to a connection being con-ducted via a higher capacity transmission channel, said channel is broken up into its constituent subsidiary channels.
Description
The invention relates to tOd.m. exchange systems.
One advantage of a tOdOm. system is that a plurality of data channels which are interlocked in terms of time may be trans-mitted independently of one another via a single t.d.m. channel.
This can ~e made in the normal manner of operation of the system and in this connection one speaks of dividing the t.d.m. channel in-to subsidiary channels. However, it is also possible to combine sub-sidiary channels in such manner that where necessary and for a specific length of time, e.g. for the duration of a connection between two specific subscribers, channels possessing a higher transmission capacity than a single subsidiary channel are formed.
However, this type of formation of channels possessing a higher transmission capacity requires that an additional signalling cri-terion should be provided to be added to the already existing signalling criteria such as call criterion, call confirmation cr~terion? connected criterion, dial request criterion and clear-~ ing signal criterion. The additional signalling criterion must ; contain an item of information stating whether a subsidiary chan-nel Is to cooperate with other subsidiary channels and if this is necessar~, how many and which further subsidiary channels are con-cerned~ Furthermore, the signalling criterion must contain an ~tem of information stating the type of operation with which a subsequent transmission is handled on this channel. This is nec-essary because in addition to an at least partially transparent transmission, a pulse-governed transmission or a transmission of information in analogue form is to be possible. A non-pulse-governed transmission can be realised e.g. by the transmission of ~, _ 2 -103~1~9 non-coded or coded scanning values. We shall refer to the information on the scanning values as a pulse telegram. In the case of non-coded transmission the pulse telegram will comprise the actual scanned values obtained during scanning of an information element. In the case of coded transmission, the pulse telegram will comprise a statement~ in coded form, concerning the po-larity of aninformation element and also the time of the polarity change. In all cases, as a result of the scanning of the practically non-isochronous signals, there are greater or lesser delays which however are subject to gi-ven fault limits. The smallest distortions occur in the transmission of co-ded scanned values since in this case a very fine time pattern is used forthe scanning of the information elements. Consequently a complete transpa-rency, which is understood as a transmission which is absolutely independent of code and speed in practice cannot be achieved in a t.d.m. system. When, therefore, we speak of a transparent transmission in the following, this is to be understood as a~transmission with a transparency which satisfies prac-tical conditions.
According to the present invention there is provided a t.d.m. ex-change system comprising a transmitting station including a transmitting store, a receiving station including a receiving store, and an exchange via which information is transmitted from the transmitting station to the re-ceiving station in time channels to which storage ceIls in the transmitting store and in the receiving store are assigned, wherein time channels may be temporarily combined to form a transmission channel having a higher channel capacity than the individual time channels, wherein, prior to a transmission ; of data necessitating such a higher channel capacity an item of command infor-mation formed at the transmitting station and an additional criterion de-noting that the information is command information are recorded into and transmitted from a storage cell of the transmitting store which is assigned to an unseized time channel, wherein in response to reception of the command ..,..}
information and the additional criterion in the exchange at least two equi-distant time channels are combined to form a higher capacity transmission channel and a desired operating mode for the subsequent data transmission is set, and wherein in response to reception of a connection clearing signal re-lating to a connection being conducted via a higher capacity transmission channel said channel is broken up into its constituent time channels.
The transmission of the command information can take place prior to the transmission of the call criterion. However, it can also simultaneously serve as call criterion. In the opposite direction, an item of command in-formation of identical format serves as a confirmation that the interconnec-tion and the setting for the operating mode have been carried out.
In the use of a programme controlled exchange system, by the evalu-ation of the oommand information, subsidiary channels can be combined in re-spect of each programme. For example, it is possible to combine for equidis-tant, transparent 50 Bd subsidiary channels to form a transparent 200 Bd chan-nel. In the event that transparent data transmission is not required, in-stead of a transparent 200 Bd channel, as a result of the evaluation of the command information, a pulse governed 2 kBd channel can be operated in pro-gramme controlled fashion. In this case however it is necessary that the 50 Bd channel should be able to be scanned at an interval which enables even ; pre-distorted signals to be transmitted and which is such that a pulse tele-gram contains 8 bits for the useful infor~ation.
The present invention will now be described by way of example and ; with reference to the drawing, which is:-a block circuit diagram of the transmitting section of a t.d.m.
_ 4 _ 1037i~9 exchange system in accordance with the present invention.
The transmitting section of the t.d.m. exchange system shown in the drawing, comprises a transmitting end store S, having storage cells SXl to SX8 each of which are assigned to one subsidiary channel of a t.d~m.
channel DXK. This store S contains all the information for transmission, namely both data and synchronising information, said synchronising information comprising for example channel numbers, and also command information. The recording of these items of information in the transmitting store will not be described since this is not fundamental to the understanding of the present inventionO Via gate circuits G5 to G7, the outputs of the transmitting store S are connected to a word register WR, which itself records the information which is to be transmitted via further gate circuits Gl to G4 in serial form into the transmitting register SR from where it is transmitted via the data channel DK. For the control of the bit-serial transmission there is provided a bit counter BZ with the subsequently connected decoder Decl. The stepping on of the bit counter takes place with a pulse train T supplied by the 5ystem. ~n the overflow of the bit counter BZ, both the word register is prepared to receive an item of information and a channel counter KNZ is stepped on. The latter is followed by a second decoder Dec2 via the outputs 2Q of which the next storage cell which follows in the time pattern is operated.
The in~ormation contained in this storage cell is then input into the word register and, under the control of the bit counter pulse train decoded in the decoder Decl, is recorded via the gates Gl to G4 into the transmitting register. In accordance with a known proposal, for synchronisationJ the channel number i.e. the count of the channel counter KNZ is fed via the gates G8 to G10 into the word register whenever the relevant storage cell, addressed b~ the channel pulse train, in the transmitting store contains no information for transmission. The fact that an item of synchronising in-formation îs being transmitted is indicated by a special criterion recorded in the last position of a storage cell.
At the transmitting station a criterion is present which indicates the unseized state of a subsidiary channel. This state can be characterised in that the storage cell which, as a result of the channel number, is assign-ed to this subsidiary channel, does not contain any information and thus the individual storage positions of the storage cell contain a 0, or in that a special marker criterion is recorded. In these cases, the corresponding storage cell can be fed with an item of command information which can be interpreted at a central point as signalling criterion. The command informa-tion contains a statement as to whether this subsidiary channel must be con-nected to other equidistant subsidiary channels, or whether the subsidiary channel is being operated by itself. Furthermore, it contains further state-ments concerning the number of equidistant subsidiary channels which are to be connected, and concerning the mode of operation with which the following data transmission must be handled. The fact that the information contained in a storage cell assigned to an unseized subsidiary channel is command informa-tion in the above sense is indicated by an additional criterion which is recorded e.g. in the form of a "1" in the last position of the relevant storage cell.
A list of possible command formats and the significance thereof as signalling criteria in t.d.m. transmission systems of various categories is shown in the following table in which t signifies transparent, tk signifi~s pulse-governed, K signifies channel and MK signifies marker criterion.
Commands MK Operating Mode- 8 kBd 64 kBd 2.048 MBd (Unseized subsidiary channel O O O) O 1 0 1Transmission of 16 t 128 t 16 t coded scanned values 50 Bd-K 50 Bd-K 10-kBd-K
1 0 0 1 ~' 4 t 32 t 4 t ~` 200-Bd-K 200-Bd-K SO-kBd-K
O 1 1 1Transmission of non- 16 t 128 t 16 t coded scanned values SO-Bd-K SO-Bd-K 10-kBd-K
.
1037~69 1 0 1 1 Transmi~sion f 4 t 32 t 4 t non-coded scanned 200-Bd-K200-Bd-K 50-kBd-K
value 1 1 1 1 Direct, pulse-govern- 4 tk 32 tk 32 tk ed transmission 2-kBd-K 2-kBd-K 64-kBd-K
.
0 0 1 1 ~ 1 tk 8 tk 4 tk 8-k8d-K 8-kBd-K 256-kBd-K
1 1 0 1 32 speech channels In the table, the first column shows the command information as a 3-bit command. The last bit alwayy contains a 1 and serves as marker criterion MK to the effect that the first three bits represent an ibem of command information. Column 2 states how the command information is inter-preted in the central system to determine ~he operating mode. Columns 3, 4 and 5 each state the subsidiary channel divisions and combinations for a 8 kBd, 64 kBd and 2.048 MBd network. Thus for example the command information 0 1 0 which, as a result of the analysis of the marker criterion MK = 1 entered in the last position of the storage cell is recognised as an ite- of command information, results in the set~ing up of the operating mode for the transmission of coded scanned v`alues. At the same time this command informa-tion signifies that it is not necessary for subsidiary channels to be inter-connected. Under this condition, in a 8 kBd network there are available 16 and in a 64 kBd network there are available 128 in each case transparent 50 Bd channels. In a 2.048 MBd network this information is evaluated as signal-ling criterion for the making available of 16 transparent 10 kBd channels via which coded scanned values are transmitted. Similarly, the command formats contained in lines 2, 3, 4, 5, 6 and 7 are also evaluated in the central sys-tem and lead e.g. to the programme-controlled setting up in the appropriate operating mode and, where necessary, to the interconnectionof individual sub-sidiary channels to form a channel of higher transmission capacity. me invention is not, of course, limited to the command formats stated in the table nor to the network 10~7169 .
categories mentioned therein.
Subsequently to the transmission of the command information which either takes place prior to the transmission of a call criterion or which is simultaneously interpreted as call criterion, in transparent channels, the polarity required in accordance with the conventional signalling is set up on the channel. For the data transmission which now follows, the bits of the data which is to be transmitted are recorded in~known manner in the transmitting store and, under the contr~l of the bit and channel pulse train, are transmitted interlocking in time via the data channel DK. The state which has been set up on the basis of the previously transmitted command information is maintained for the duration of a cormection. In a program~e-controlled system the command information may be stored at a central point possibly in one zone of the central store, until the end of the connection.
However, storage is also possible at the receiving station i.e. in the receiving store.
A channel of higher transmission capacity which has been formed by the combination of a plurality of equidistant subsidiary channels is broken up by the analysis of the clearing signal of the connection. In order to not restrict the transparency of a channel as a result of the analysis of the clearing signal, which, in accordance with conventional signalling, is time-dependent, it as already known to transmit the clearing signal on a signalling channel individually assigned to the data channel or on a central signalling channel. For the formation of an individual signalling channel, it is possible, in cases in which coded scanned values are transmitted as so-called pulse telegrams, to agree upon a specific pulse telegram as clearing signal whish then, however, is unable to represent a code signal which indicates a scanning period. As in practice every pulse telegram indicating a time interval possesses a 1 at least at one position, it is possible to agree upon a pulse telegram consisting of a sequence of ~'0~ s as clearing 1`~)37~9 signal.
In the transmission of non-coded scanned values, the clearing signal can be realised by a bit pattern which does not occur in normal operation. This is possible because even in the event of signals which are considerably pre-distorted, at the maximum only t~o polarity changes can occur in a pulse telegram. Thus a signal wh~chhcontains a 1 at more than two positions can be transmitted asclearing signal. The positions of this type of pulse telegram~ which may be interpreted as clearing signal are thus e.g. alternately filled with a 1 and a 0-In pulse-governed connections the clearing signal can e.g. take the form of the "end of transmission" signal which is transmitted in the 8 element~ code.
.
! .
One advantage of a tOdOm. system is that a plurality of data channels which are interlocked in terms of time may be trans-mitted independently of one another via a single t.d.m. channel.
This can ~e made in the normal manner of operation of the system and in this connection one speaks of dividing the t.d.m. channel in-to subsidiary channels. However, it is also possible to combine sub-sidiary channels in such manner that where necessary and for a specific length of time, e.g. for the duration of a connection between two specific subscribers, channels possessing a higher transmission capacity than a single subsidiary channel are formed.
However, this type of formation of channels possessing a higher transmission capacity requires that an additional signalling cri-terion should be provided to be added to the already existing signalling criteria such as call criterion, call confirmation cr~terion? connected criterion, dial request criterion and clear-~ ing signal criterion. The additional signalling criterion must ; contain an item of information stating whether a subsidiary chan-nel Is to cooperate with other subsidiary channels and if this is necessar~, how many and which further subsidiary channels are con-cerned~ Furthermore, the signalling criterion must contain an ~tem of information stating the type of operation with which a subsequent transmission is handled on this channel. This is nec-essary because in addition to an at least partially transparent transmission, a pulse-governed transmission or a transmission of information in analogue form is to be possible. A non-pulse-governed transmission can be realised e.g. by the transmission of ~, _ 2 -103~1~9 non-coded or coded scanning values. We shall refer to the information on the scanning values as a pulse telegram. In the case of non-coded transmission the pulse telegram will comprise the actual scanned values obtained during scanning of an information element. In the case of coded transmission, the pulse telegram will comprise a statement~ in coded form, concerning the po-larity of aninformation element and also the time of the polarity change. In all cases, as a result of the scanning of the practically non-isochronous signals, there are greater or lesser delays which however are subject to gi-ven fault limits. The smallest distortions occur in the transmission of co-ded scanned values since in this case a very fine time pattern is used forthe scanning of the information elements. Consequently a complete transpa-rency, which is understood as a transmission which is absolutely independent of code and speed in practice cannot be achieved in a t.d.m. system. When, therefore, we speak of a transparent transmission in the following, this is to be understood as a~transmission with a transparency which satisfies prac-tical conditions.
According to the present invention there is provided a t.d.m. ex-change system comprising a transmitting station including a transmitting store, a receiving station including a receiving store, and an exchange via which information is transmitted from the transmitting station to the re-ceiving station in time channels to which storage ceIls in the transmitting store and in the receiving store are assigned, wherein time channels may be temporarily combined to form a transmission channel having a higher channel capacity than the individual time channels, wherein, prior to a transmission ; of data necessitating such a higher channel capacity an item of command infor-mation formed at the transmitting station and an additional criterion de-noting that the information is command information are recorded into and transmitted from a storage cell of the transmitting store which is assigned to an unseized time channel, wherein in response to reception of the command ..,..}
information and the additional criterion in the exchange at least two equi-distant time channels are combined to form a higher capacity transmission channel and a desired operating mode for the subsequent data transmission is set, and wherein in response to reception of a connection clearing signal re-lating to a connection being conducted via a higher capacity transmission channel said channel is broken up into its constituent time channels.
The transmission of the command information can take place prior to the transmission of the call criterion. However, it can also simultaneously serve as call criterion. In the opposite direction, an item of command in-formation of identical format serves as a confirmation that the interconnec-tion and the setting for the operating mode have been carried out.
In the use of a programme controlled exchange system, by the evalu-ation of the oommand information, subsidiary channels can be combined in re-spect of each programme. For example, it is possible to combine for equidis-tant, transparent 50 Bd subsidiary channels to form a transparent 200 Bd chan-nel. In the event that transparent data transmission is not required, in-stead of a transparent 200 Bd channel, as a result of the evaluation of the command information, a pulse governed 2 kBd channel can be operated in pro-gramme controlled fashion. In this case however it is necessary that the 50 Bd channel should be able to be scanned at an interval which enables even ; pre-distorted signals to be transmitted and which is such that a pulse tele-gram contains 8 bits for the useful infor~ation.
The present invention will now be described by way of example and ; with reference to the drawing, which is:-a block circuit diagram of the transmitting section of a t.d.m.
_ 4 _ 1037i~9 exchange system in accordance with the present invention.
The transmitting section of the t.d.m. exchange system shown in the drawing, comprises a transmitting end store S, having storage cells SXl to SX8 each of which are assigned to one subsidiary channel of a t.d~m.
channel DXK. This store S contains all the information for transmission, namely both data and synchronising information, said synchronising information comprising for example channel numbers, and also command information. The recording of these items of information in the transmitting store will not be described since this is not fundamental to the understanding of the present inventionO Via gate circuits G5 to G7, the outputs of the transmitting store S are connected to a word register WR, which itself records the information which is to be transmitted via further gate circuits Gl to G4 in serial form into the transmitting register SR from where it is transmitted via the data channel DK. For the control of the bit-serial transmission there is provided a bit counter BZ with the subsequently connected decoder Decl. The stepping on of the bit counter takes place with a pulse train T supplied by the 5ystem. ~n the overflow of the bit counter BZ, both the word register is prepared to receive an item of information and a channel counter KNZ is stepped on. The latter is followed by a second decoder Dec2 via the outputs 2Q of which the next storage cell which follows in the time pattern is operated.
The in~ormation contained in this storage cell is then input into the word register and, under the control of the bit counter pulse train decoded in the decoder Decl, is recorded via the gates Gl to G4 into the transmitting register. In accordance with a known proposal, for synchronisationJ the channel number i.e. the count of the channel counter KNZ is fed via the gates G8 to G10 into the word register whenever the relevant storage cell, addressed b~ the channel pulse train, in the transmitting store contains no information for transmission. The fact that an item of synchronising in-formation îs being transmitted is indicated by a special criterion recorded in the last position of a storage cell.
At the transmitting station a criterion is present which indicates the unseized state of a subsidiary channel. This state can be characterised in that the storage cell which, as a result of the channel number, is assign-ed to this subsidiary channel, does not contain any information and thus the individual storage positions of the storage cell contain a 0, or in that a special marker criterion is recorded. In these cases, the corresponding storage cell can be fed with an item of command information which can be interpreted at a central point as signalling criterion. The command informa-tion contains a statement as to whether this subsidiary channel must be con-nected to other equidistant subsidiary channels, or whether the subsidiary channel is being operated by itself. Furthermore, it contains further state-ments concerning the number of equidistant subsidiary channels which are to be connected, and concerning the mode of operation with which the following data transmission must be handled. The fact that the information contained in a storage cell assigned to an unseized subsidiary channel is command informa-tion in the above sense is indicated by an additional criterion which is recorded e.g. in the form of a "1" in the last position of the relevant storage cell.
A list of possible command formats and the significance thereof as signalling criteria in t.d.m. transmission systems of various categories is shown in the following table in which t signifies transparent, tk signifi~s pulse-governed, K signifies channel and MK signifies marker criterion.
Commands MK Operating Mode- 8 kBd 64 kBd 2.048 MBd (Unseized subsidiary channel O O O) O 1 0 1Transmission of 16 t 128 t 16 t coded scanned values 50 Bd-K 50 Bd-K 10-kBd-K
1 0 0 1 ~' 4 t 32 t 4 t ~` 200-Bd-K 200-Bd-K SO-kBd-K
O 1 1 1Transmission of non- 16 t 128 t 16 t coded scanned values SO-Bd-K SO-Bd-K 10-kBd-K
.
1037~69 1 0 1 1 Transmi~sion f 4 t 32 t 4 t non-coded scanned 200-Bd-K200-Bd-K 50-kBd-K
value 1 1 1 1 Direct, pulse-govern- 4 tk 32 tk 32 tk ed transmission 2-kBd-K 2-kBd-K 64-kBd-K
.
0 0 1 1 ~ 1 tk 8 tk 4 tk 8-k8d-K 8-kBd-K 256-kBd-K
1 1 0 1 32 speech channels In the table, the first column shows the command information as a 3-bit command. The last bit alwayy contains a 1 and serves as marker criterion MK to the effect that the first three bits represent an ibem of command information. Column 2 states how the command information is inter-preted in the central system to determine ~he operating mode. Columns 3, 4 and 5 each state the subsidiary channel divisions and combinations for a 8 kBd, 64 kBd and 2.048 MBd network. Thus for example the command information 0 1 0 which, as a result of the analysis of the marker criterion MK = 1 entered in the last position of the storage cell is recognised as an ite- of command information, results in the set~ing up of the operating mode for the transmission of coded scanned v`alues. At the same time this command informa-tion signifies that it is not necessary for subsidiary channels to be inter-connected. Under this condition, in a 8 kBd network there are available 16 and in a 64 kBd network there are available 128 in each case transparent 50 Bd channels. In a 2.048 MBd network this information is evaluated as signal-ling criterion for the making available of 16 transparent 10 kBd channels via which coded scanned values are transmitted. Similarly, the command formats contained in lines 2, 3, 4, 5, 6 and 7 are also evaluated in the central sys-tem and lead e.g. to the programme-controlled setting up in the appropriate operating mode and, where necessary, to the interconnectionof individual sub-sidiary channels to form a channel of higher transmission capacity. me invention is not, of course, limited to the command formats stated in the table nor to the network 10~7169 .
categories mentioned therein.
Subsequently to the transmission of the command information which either takes place prior to the transmission of a call criterion or which is simultaneously interpreted as call criterion, in transparent channels, the polarity required in accordance with the conventional signalling is set up on the channel. For the data transmission which now follows, the bits of the data which is to be transmitted are recorded in~known manner in the transmitting store and, under the contr~l of the bit and channel pulse train, are transmitted interlocking in time via the data channel DK. The state which has been set up on the basis of the previously transmitted command information is maintained for the duration of a cormection. In a program~e-controlled system the command information may be stored at a central point possibly in one zone of the central store, until the end of the connection.
However, storage is also possible at the receiving station i.e. in the receiving store.
A channel of higher transmission capacity which has been formed by the combination of a plurality of equidistant subsidiary channels is broken up by the analysis of the clearing signal of the connection. In order to not restrict the transparency of a channel as a result of the analysis of the clearing signal, which, in accordance with conventional signalling, is time-dependent, it as already known to transmit the clearing signal on a signalling channel individually assigned to the data channel or on a central signalling channel. For the formation of an individual signalling channel, it is possible, in cases in which coded scanned values are transmitted as so-called pulse telegrams, to agree upon a specific pulse telegram as clearing signal whish then, however, is unable to represent a code signal which indicates a scanning period. As in practice every pulse telegram indicating a time interval possesses a 1 at least at one position, it is possible to agree upon a pulse telegram consisting of a sequence of ~'0~ s as clearing 1`~)37~9 signal.
In the transmission of non-coded scanned values, the clearing signal can be realised by a bit pattern which does not occur in normal operation. This is possible because even in the event of signals which are considerably pre-distorted, at the maximum only t~o polarity changes can occur in a pulse telegram. Thus a signal wh~chhcontains a 1 at more than two positions can be transmitted asclearing signal. The positions of this type of pulse telegram~ which may be interpreted as clearing signal are thus e.g. alternately filled with a 1 and a 0-In pulse-governed connections the clearing signal can e.g. take the form of the "end of transmission" signal which is transmitted in the 8 element~ code.
.
! .
Claims (5)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A t.d.m. exchange system comprising a transmitting station includ-ing a transmitting store, a receiving station including a receiving store, and an exchange via which information is transmitted from the transmitting station to the receiving station in time channels to which storage cells in the transmitting store and in the receiving store are assigned, wherein time channels may be temporarily combined to form a transmission channel having a higher channel capacity than the individual time channels, wherein prior to a transmission of data necessitating such a higher channel capacity an item of command information formed at the transmitting station and an additional criterion denoting that the information is command information are recorded into and transmitted from a storage cell of the transmitting store which is assigned to an unseized time channel, wherein in response to reception of the command information and the additional criterion in the exchange at least two equidistant time channels are combined to form a higher capacity trans-mission channel and a desired operating mode for the subsequent data trans-mission is set, and wherein in response to reception of a connection clearing signal relating to a connection being conducted via a higher capacity transmission channel said channel is broken up into its constituent time channels.
2. A system as claimed in claim 1, wherein the transmission of the command information takes place prior to the transmission of a call criterion, and wherein, to signal that the formation of the higher capacity transmission channel and the setting to the relevant operative mode have been carried out, the exchange transmits an item of command information of identical for-mat back to the transmitting station.
3. A system as claimed in claim 1, in which transmission of coded scanned values is effected and wherein the connection clearing signal is con-stituted by a pulse telegram having a bit sequence which does not represent any item of information indicating a scanning time.
4. A system as claimed in Claim 1, in which transmission of non-coded scanned values is effected and wherein the connection clearing signal is con-stituted by a pulse telegram having more than two polarity changes.
5. A system as claimed in Claim 1, in which pulse-governed transmission is effected and wherein the connection clearing signal is constituted by an "end of transmission" signal in 8 element code.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE2241636A DE2241636A1 (en) | 1972-08-25 | 1972-08-25 | SIGNALING PROCEDURE IN TIME MULTIPLEX SWITCHING SYSTEMS |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1037169A true CA1037169A (en) | 1978-08-22 |
Family
ID=5854421
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA178,750A Expired CA1037169A (en) | 1972-08-25 | 1973-08-14 | T.d.m. exchange systems |
Country Status (10)
| Country | Link |
|---|---|
| BE (1) | BE804010A (en) |
| BR (1) | BR7306564D0 (en) |
| CA (1) | CA1037169A (en) |
| CH (1) | CH557120A (en) |
| DE (1) | DE2241636A1 (en) |
| FR (1) | FR2197292B1 (en) |
| GB (1) | GB1432168A (en) |
| IT (1) | IT1030560B (en) |
| NL (1) | NL7311398A (en) |
| ZA (1) | ZA735595B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3176395D1 (en) * | 1981-04-30 | 1987-10-01 | Ibm | Process to determine the configuration of the active channels in a multiflex communication system, and device therefor |
| GB8618424D0 (en) * | 1986-07-29 | 1986-09-03 | Leslie I M | Data rate channel for digital network |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL295510A (en) * | 1962-07-19 | |||
| FR1513888A (en) * | 1966-06-27 | 1968-02-16 | Nippon Telegraph & Telephone | Communication network |
| US3639693A (en) * | 1968-11-22 | 1972-02-01 | Stromberg Carlson Corp | Time division multiplex data switch |
| DE1947262C3 (en) * | 1969-09-18 | 1973-11-15 | Siemens Ag | Method for data transmission between two participants in a data network |
| US3668645A (en) * | 1970-05-25 | 1972-06-06 | Gen Datacomm Ind Inc | Programable asynchronous data buffer having means to transmit error protected channel control signals |
| US3699525A (en) * | 1970-11-27 | 1972-10-17 | Honeywell Inf Systems | Use of control words to change configuration and operating mode of a data communication system |
| US3705267A (en) * | 1971-09-03 | 1972-12-05 | Bell Telephone Labor Inc | Supervisory circuit for monitoring the formation and termination of interconnections in a time-division switch |
-
1972
- 1972-08-25 DE DE2241636A patent/DE2241636A1/en active Pending
-
1973
- 1973-06-13 CH CH856073A patent/CH557120A/en not_active IP Right Cessation
- 1973-07-10 FR FR7325279A patent/FR2197292B1/fr not_active Expired
- 1973-07-24 GB GB3517573A patent/GB1432168A/en not_active Expired
- 1973-08-14 CA CA178,750A patent/CA1037169A/en not_active Expired
- 1973-08-15 ZA ZA735595A patent/ZA735595B/en unknown
- 1973-08-17 NL NL7311398A patent/NL7311398A/xx not_active Application Discontinuation
- 1973-08-24 BE BE134923A patent/BE804010A/en unknown
- 1973-08-24 IT IT28146/73A patent/IT1030560B/en active
- 1973-08-24 BR BR6564/73A patent/BR7306564D0/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| FR2197292A1 (en) | 1974-03-22 |
| BR7306564D0 (en) | 1974-07-11 |
| NL7311398A (en) | 1974-02-27 |
| AU5933373A (en) | 1975-02-20 |
| ZA735595B (en) | 1974-07-31 |
| BE804010A (en) | 1974-02-25 |
| DE2241636A1 (en) | 1974-03-07 |
| GB1432168A (en) | 1976-04-14 |
| IT1030560B (en) | 1979-04-10 |
| CH557120A (en) | 1974-12-13 |
| FR2197292B1 (en) | 1977-09-09 |
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