DE2312449A1 - DATA TRANSFER CENTER - Google Patents

Description

Our reference: P 2205

PLESSEY HANDEL UND INVESTMENTS AG Gartenstrasse 2
6500 train. Switzerland

Data exchange center

The invention relates to a data exchange, those using time division multiplexing in national or similar data switching networks can be used, and it relates in particular to the switching functions of detection and generation of network notification characters.

A data switching center in which time division multiplex switching methods are used is described in patent application P 21 57 470.9. The network reporting system supplied by such a center is of the "in-band ⁿ " type, and it is typically a system with durability testing. Typically, each time division multiplexed channel consists of information in the form of a 10-bit group with eight character bits, a reporting bit and a synchronization bit. The status of the message bit is used to indicate the meaning of the associated character (ie whether the character is a data character or a network message character).

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The puncturing of the network message character detection at the control center requires (I) the demultiplexing of the incoming messages Multiplex groups into individual channels, (II) the examination of the Message bits of each of the demultiplexed channels, (III) the registration of the content of the bit group when a network message character is indicated, and (IV) the implementation of a durability test on the registered notification symbol. The function of the network message character generation, however, requires the insertion of selected message characters into certain channels of the outgoing multiplex groups from the control center. In the case of the patent application P 21 57 470.9 described switching system these functions of the determination and the generation of message characters are of their own Devices executed corresponding to the input and output peripherals of the switch through-hole are assigned to the network.

With the help of the invention, a possible solution for the determination and generation of network message characters is intended within a data switching center that works using time division multiplex switching methods, can be specified.

According to the invention is a data exchange for Operation of subscriber stations with several data transmission speed categories in alternating traffic, each subscriber station from a corresponding discrete incoming and outgoing time division multiplex channel is served, characterized in that a time division multiplexed channel switching network it is provided that a number of incoming bus lines and an equal number of outgoing bus lines contains, which are arranged in pairs so that each pair has corresponding incoming and outgoing channels

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a group of subscriber stations with the same data transmission rate category in the same synchronous, character interleaved, multiplex time gap appearance order leads, with multiple timing cords for each data rate category are provided, each of which has a plurality of time switch cord storage locations, and that each Subscriber station that is operated by the control center, exclusively in a selected manner a corresponding, provided for a data transmission speed category Time-renting cord storage space allocated at all times regardless of the operating status of the subscriber station is.

A further development of the invention consists in the fact that each time switching cord storage location has a line status section contains, and that each timing line with means to detect the occurrence a network message character is provided.

Another embodiment of the invention is that each time switch string memory location is one Character memory section contains, and that means for writing network message characters generated at the center siiid provided in the data storage section;

An advantageous further embodiment of the invention is that the incoming and outgoing busses terminate on a switching network that each Time switch string storage contains a storage section for a through network control address; that means for scanning the memory locations of a string in synchronism with the times of appearance of the time division multiplexed channel on the incoming busbars of the corresponding data transmission speed category.

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and that the is the switching network control address containing memory section is arranged such that it matches the identity of the incoming bus is programmable, on .der the channel occurs that belongs to the subscriber station that is currently is assigned to the corresponding line storage space.

An embodiment of the invention is shown in the drawing.

Pig.1 a simplified diagram of part of a data exchange ,

Fig. 2 shows part of the look-through network and one Cord storage space when used to perform the message character detection and message character generation function the circuit,

Fig. 3 together with Fig. 4. schematically the functions of the Look-through network when performing an alternate traffic data transmission and

Figure 5 is a flow diagram of the functions performed by the switch control processor are performed on all call connection operations.

The data exchange of Fig.1 consists of (I) a network coupling multiplex unit NIME, (II) Spatial / temporal / spatial switching network SN and (III) from a stored-program common control complex SPPC.

1. The network coupling multiplex unit NIME forms the Coupling unit between the time division multiplex switching

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lines EL1 to ELN and the switching network. the The exchange is designed so that it has four basic bit rates on the subscriber station lines supplied, namely 800 bits per second, 3312 kb / s, 12.8 kb / s, and 64 kb / s. Each time division multiplex channel (i.e. each subscriber station or trunk gap) exists from a 10-bit group, of which eight bits are for data be used. This gives effective. Subscriber bit speeds of 600 b / s, 2.4 kb / s, 9.6 kb / s and 48 kb / s. Intermediate bit rates are determined by inserting empty groups in the multiplex frame scored when required.

The network coupling multiplex unit NIME is used to convert the switching lines EL1 to ELN to demultiplex incoming bit sequences and to the switching trunk lines assigned to a transmission speed Typically, each switch trunk transmits character-interleaved Multiplex groups at a rate of 64 kb / s that is a single user data bit rate are assigned, the pulse frame being built on the basis of universal switching and time-aligned corresponding outward and return channels are provided. In Fig.1 there are only three Switch buses H01 / HI1, H02 / HI2 and HON / HIN are shown and assume that they are all have the same data bit speed. the Network coupling multiplex unit NIME is designed in such a way that that they have one for each user data bit rate Group of switching trunks generated.

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Subscriber stations get access to the data switching center according to one of three possibilities.

(a) Direct Access

Direct access to the data exchange center applies to those subscriber stations which are located at the location of the exchange. Local subscriber stations operating asynchronously with respect to the exchange are coupled with the aid of a device within the multiplex unit NIME, which means that they are converted to and from network groups ( i.e. 10 bits per group at one of the basic bit rates of the subscriber station lines) * The synchronous network group is therefore regarded as the basic local area input variable in the exchange »64 kb / s multiplex trunk lines _{or the like assigned to a transmission speed}

(b) Access via a 64 kb / s multiplex channel

Those not located directly at the location of the Yermittlimgsstell® Subscriber stations can be on their local telephone. exchange on 64 kb / s ~ multiplexed channels will. These multiplex channels contain a Mixture of drsi lower network speeds, and part of the multiplex channel capacity is multiplex synchronization as well as related functions The multiplex unit NIME is designed in such a way that it demultiples the incoming bit sequences and opens the channels the associated, a tfesr-traguagsgesoh Speed assigned Switch trunk lines distributed.

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( c) Access via 2.048 Mb / s digital line systems.

Subscriber stations with which the 64 kb / s multiplexing and which are quite far away from the exchange can be done with the second Multiplexers on 2.048 Mb / s digital line systems are further multiplexed; the second multiplexer can be attached to the group switching centers of the telephone network.Pur the data traffic three 33g64 kb / s multiplex channels used in the 2.048 Mb / s multiplex channel, each 64 kb / s multiplex channel is assigned to a transmission rate (unirate), i.e. the transmission of a single network user data bit transmission rate assigned. The network coupling multiplexing unit NIME can the 2.048 Mb / s multiplex into its thirty 64 kb / s sub-multiplexes split, each served by a switching trunk of the corresponding group will.

(d) trunk access .

Each long-distance line consists of a transmission speed assigned 64 kb / s channels on multiplex groups, multiplexed onto 2.048 Mb / s digital line systems. Some of the 64 kb / s channels on the digital line system are the transmission of a packaged switched traffic (packet switched traffic) assigned. The network coupling multiplex unit NIME can convert the 2.048 Mb / s multiplex into its 64 kb / s sub-multiplexes split, and each of these sub-multiplexes is (I) from a switching trunk to the associated Group or (II) when transmitting packaged-switched traffic from a packet-switching collective -

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line TPH served by the multiplex unit NIME extends to the packet storage area in the control center SPCC.

2. The switching network SN provides both the spatial and the temporal switching functions that are required for the exchange of calls between subscriber stations that end at the exchange or pass through the exchange. As already mentioned above, FIG. 1 shows a very simplified version of the switching network SN, which consists of a spatial switching section which (a) connects the switching trunks, for example H01 / HI1, H02 / HI2 and HON / HIN, assigned to a transmission speed associated data rate devices of the temporal switch section for switched calls (circuit switched cords) and (b) connects the temporal switch section to the packet trunking PHO and PHI for packaged switched calls. The time switching section contains several so-called time switching cords, which are shown in Fig. 1 as cords C1, C2 to CZ. The time switching cords are devices assigned to a transmission speed, and there is one time switching cord for each switching busbar pair with a few additional cords for security purposes. Each switching cord assigned to a transmission speed consists of a common control logic block and several memory locations, one of which is available for each channel of the corresponding 64 kb / s multiplex assigned to a transmission speed; each memory location is used to store a data character for the time misalignment

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period is used between two alternating traffic channels. At each memory location there is (a) a status code group,

(b) an agency information crossing point address,

(c) a transmission address and (d) a data character are stored. The meaning of each of these sections is considered in more detail below. Sufficient at this point it indicates that each channel used on all switch buses is a discrete string storage location in a corresponding time switching cord assigned to a transmission speed without Consideration of its operating status (i.e. occupied or free) is assigned. Any string storage space can be addressed synchronously with the appearance of the associated channel, and the switch trunk crosspoint address section of the corresponding memory location is programmed with the identity of the switching trunk assigned to a transmission speed on which the assigned channel is appears.

3. The control complex SPCC supplies the control algorithm for the control of the switching network; it is typically a 'multiprocessor complex controlled by a memory program. The control complex is connected to the Zeitverraittlungssdnüren via lines CL1, CL2 and CLZ. The common control complex also contains packetization and. Packet resolution arrangements and a packet store. The information that is to be stored in the packet memory is supplied in packetized form via the trunk line TPH from the trunk lines or is combined into a packetized form by the trunk line PHO. In the same way, the multiple lines TPH and TPI are used for distributing the packetized information from the packet memory.

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How the switching systems work.

has already been mentioned above, every incoming channel ending at the exchange is at every time, point a cord storage location in one of the corresponding data rate timing cords assigned. If the channel is free, the allocated string memory space is used to set the channel for alarm signals to monitor and signal signals generated in the exchange to the subscriber station served by the channel or to send back the pipeline. This case is shown in FIG. 2 for a single one, the memory space The channel assigned to the CLX is shown schematically. The individual word storage locations in the time switch string memory CQs become cyclical and synchronous with the appearance of these channels on the 64 kb / s time division switch buses read and the string control logic C exercises depending on the memory space contained in the read Information from various functions.

Each line storage location, for example the line storage location CLX, contains four information storage fields A to D In field A, the station status field, an encoded information byte is stored which shows the status of the corresponding channel in the last frame indicates. Each time the line memory location CLX is read, the information contained in field A is saved with the aid of a Comparison circuit COM in the line control logic CCL with the incoming message character of the corresponding channel compared if such a signal is present. The comparison circuit COM detects every change in the state of the channel and reported via the status change line SCL to the control unit SPCC of FIG.

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The comparison circuit COM is also used to update the station status code group in field A. To bring stand. That of a string storage space within A channel served by a 64kb / s multiplex group is defined by its cyclic addressing gap, however the multiplex channel (i.e. the exchange trunk) can be configured according to the number programmed in field B. Information of the line storage space, so the collection itungskreuzungspunktadres se, can be changed. From Fig. 2 it can be seen that field B defines switch trunk H02 / HI2, and after each reading of the string memory location CLX, the intersection points X2I and X20 are activated. With this arrangement, one will open at this channel time the incoming switching bus HI2 entered characters into the comparison circuit COM, while the information contained in field D of the string storage location s CLX to the outgoing exchange trunk H02 is given.

In the patent application P 21 57 470.9 it is described that each locally terminated subscriber station in the connected but free state is subjected to a permanent free-free signal exchange with the data exchange. Thus, the central office must generate the responding idle signal for the outbound transmission at the required channel time on the particular outbound switch. This function is achieved by programming field D with a free reporting signal along with a display in station status field A to indicate that field D should be held.

From the above description, it can be seen that each input channel overflows from its switch trunk a switching network crosspoint is routed to a time switch only whenever it is on its

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incoming switch trunk appears · The timing switch that actually connects a particular channel operated, however, if necessary, simply by reprogramming the intersection address (in field B) and the control can be changed by the control complex. An important function that is needed under these circumstances is the update of a "connection list" showing the correlation between the string space and the input channel. Appropriately, such a connection list is contained in the memory of the control complex, and it can be manipulated under the control of the control complex software.

The use of the time switching cords for the detection and generation of alarm signals makes it necessary to include in the control algorithm of the switching network the possibility of dynamic reassignment of channels between cords of the same user data rate. This is necessary because the time switch function is greatly simplified when the two cord memory locations for connecting a call are within the same time switch cord. FIG. 3 and FIG. 4 schematically show the processes which are carried out when connecting two subscriber stations ZX and 2NY in the time gaps X and Y of the switching channels. FIG. 3 shows the operations which are carried out when the channel assigned to the subscriber station 2X appears, while FIG. 4 shows the operations which are carried out when the channel assigned to the subscriber station NY appears.

First of all, FIG. 3 is now considered, from which it can be seen is that both subscriber stations are from the same Time exchange cord CQ can be operated. The cord

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The memory location CLX in the time switching cord CQ is programmed in the fields BX and CX with the intersection address of the trunk serving the subscriber station 2X (i.e. the switching trunk H02 / HI2) or with the transmission address of the other cord storage location involved in the call (i.e. the cord storage location CLY). The AX field is set according to the current status of the call. If channel X appears springy , the line memory location CLX is read, and the junction points Χ2Έ and X2O are activated by the information contained in field BX at the beginning of this gap period. The character contained in field DX is fed by the cord control logic to the outgoing exchange trunk H02, while the data character present on the incoming exchange trunk H02 is taken over within the cord control logic. At the end of the channel appearance gap period of channel X, the transmission address contained in field CX is used to address the partner cord storage location (ie, cord storage location CLY) of the call, and the accepted, arrived data character is written in field DY. The field DY therefore receives the data character generated by the subscriber station 2X.

With reference to FIG. 4, the respective at ! Appearance of the Y channel. The string storage space CLY in the string CQ is in the Fields BY and CY with the intersection address of the bus serving the subscriber station NY (d # h. the exchange trunk line HON / HIN) or with the transmission address of the other party involved in the call Programmed line memory card (i.e. the line memory location CLX). Every occurrence of channel Y

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the string memory location CLY is read, which results has ,, that the intersection points XNO and XKI through the in the field BY contained information at the beginning of this period Channel appearance gap can be activated. That in field DY The characters contained are entered by the string control logic into the outgoing exchange trunk line HOK, while the data character present on the incoming switching trunk HIN within the string control logic is taken over. At the end of the appearance gap of channel Y the transmission address in the GY field is used to to address the partner cord storage location CLX of the call, and the accepted incoming data character is in the field DX written * The field DX therefore receives this from the subscriber station NY generated data characters. The above statements relate to a case in which subscriber stations involved, but they apply equally to Long distance calls and, consequently, for telecommunication channels.

From the above description of FIGS. 3 and 4, it is assumed that in general the complete connection for a Call using a single time switch will be produced. In many cases the two will be joined Channels initially for the purpose of signaling · determination of different time switching cords served. Therefore, when establishing a connection between two channels, a search must be carried out so that a suitable time switch is found to service both channels of the call. This in Fig. 5 The search process represented in a flow diagram includes the interrogation of the above-mentioned by the control complex software stored connection list.

The following description of Fig.5 is in the steps of the flowchart and it relates to the Connect two channels α and ß necessary search process

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The channel <* is assumed to be in the time gap X appears on the operator trunk and that it is currently being served by time operator line A, while the channel β is assumed to occupy the time gap Y on a switching bus and is currently being served by time switch B.

S1; Querying the list at stations β and ß

In this step, the connection list is queried for the entry belonging to the two channels α and ß, so that the identity of cords A and B can be established.

S2: cord A = cord B?

In this step, the identity of string A is compared with the identity of string B. When their identities are the same (i.e. if channels α and ß are currently being served by the same line), then becomes the search process obviously ends after the determined gaps X and Y marked as busy in the connection list. If the identities of the cords A and B are not the same, step S4 is carried out,

S4; Is there a gap Y in line A?

In this step, the connection list at the entry belonging to gap Y in cord A is queried in order to determine whether this loophole can be used. Typically, the gap Y in cord A can currently be straight (I) not be used at all, (II) another free ' Be assigned to a channel or (III) assigned to another channel involved in an unrelated call. the Cases (I) and (II) cause the "yes" answer in step S4, ' what the execution of steps S5 and S6 entails,

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while case (III) causes the "no" answer that the execution of step S7 has the consequence

S5: Transfer from ß to gap Y in cord A

In this step, the connection list and the switching network are changed so that the gap Y is the Cord A is assigned to the channel ß. This switch-through network reassignment process is carried out by the Control complex executed, which in the field BY of the string storage location CLY of the string A, the bus crossing point address the trunk line serving the channel ß writes.

S6: Transfer the channel in the gap Y of the cord A to the gap Y of the cord B.

In this step, the port list and the switching network changed so that the channel previously served by the gap Y of the cord A, if one is present, now the gap Y is assigned to cord B (i.e. the cord that was previously assigned to channel ß was). This reassignment of the through-connection network is carried out by adding storage space to the BY field of the string. CLY string B is the crosspoint address of the newly assigned channel (i.e. the channel that was previously assigned to the string memory) cherplatz CLY was assigned to string A) is written to the switching trunk. After completion of the above-described process, step S3 is carried out before the search process is ended.

S7: gap X free in cord B?

If channel β cannot be assigned to cord A,

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^{an M} no ^w answer results in step S4, and step S7 has the consequence that the connection list is queried at an entry relating to gap X in cord B to determine whether this gap can be used. Typically the gap'X in the string B can currently (I) not be used at all, (II) be assigned to another free channel or (III) be assigned to an occupied channel. In cases (I) and (II), a "yes" answer results in step S7, which results in steps S8 and S9 being carried out, while in case (III) a "no" answer is generated which entails the execution of step S10.

58: Transfer of α to gap X in cord B.

In this step, the connection list and the switching network are changed so that the gap X the cord B is assigned to the channel α. The hay allocation process of the Duröhschaltetzverks is carried out by the fact that in the field BX of the string memory location CLX in the string B, the cross point address for the switching trunking serving the channel α is written.

59: Transfer of the channel in the gap X of the cord B

to gap X of cord A.

In this step, the connection list and the switching network are changed so that the previous one from the channel serving gap X in cord B is now assigned to gap X in cord A (i.e. the cord, which was previously assigned to channel α) · The intersection point address in the BX field is reprogrammed so that they

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the switching trunk determines the over-? served channel. After completing the above Operations, step S3 is carried out to update the connection list before the search process is terminated.

S10 t free gaps X and Y in another string?

If the required to operate the two channels Connection, neither the A nor the B line can be used, then a search is performed to find determine whether the gaps X and Y are in any other Cord are free. One of the so-called reserve lines mentioned above could typically be used in this process provided for security purposes. If another string can be used, the Steps S11, S12. And S13 carried out so that the Gaps X and Y of the cords A and B served channels are exchanged for the gaps χ and y of the reserve cord. These operations require suitable reprogramming of the Bx and By fields of the string memory locations involved in a manner analogous to the processes described above If there are no cords in which the gaps χ and y are available, then step SI4 is carried out.

S14; Rearrangement of the line space allocation .

This step is used to make the existing calls rearrange in such a way that the gaps χ and y are in a communication line be made available · With a sufficient rearrangement it is always possible to obtain the one you want Connect when there are more timing cords than switch trunk pairs (i.e. if the switching network is theoretically not blocked)

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From the above description it can be seen that the search process first tries to find one or the other to lay the other channel in the other cord? if this does not work, then both channels are tried to lay another cord in appropriate gaps, and if this is still not possible, then all existing calls rearranged.

However, there remains a call situation that depends on the search process described above cannot be operated; .this situation relates to the connection of channels, that have different switch buses but the same gap time · The difficulty arises because a timing cord only treats a single channel in each time gap can. This case can be served by having two cords and two storage locations within each cord be used.

Let us consider the case where two channels to be connected by gaps r of two separate cords M and N to be served. In this case, the search process looks for two similarly accommodated gap memory locations (e.g. s) in strings M and N that are available. The two channels, namely the gap r in the cord M and the gap r in the cord N are then connected in a normal manner to the s-gap channels within its own Cords "attached". As a result, the data of the channel rM in the storage location stf and the data of the channel rN stored in memory location sN each time the gap r appears. During the gap s, the at the storage space sM stored data via a first blind bus line (for example the DHX bus line from. Fig. 1) to the memory location rN, while the am

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Storage space sN stored data on a second Blind manifold (for example the DHT manifold of Fig. 1) are transferred to the memory location rM.

From the above description it can be seen that the Datenvermittluhgszentrale described to each incoming channel of the control center assigned cord storage space and that the assigned cord storage space used to perform the process of determining and generating network notification characters can be. This mechanism therefore eliminates the need for dedicated peripheral equipment of the switch-through network assigned to these functions.

In a modification of the arrangement described above, the dummy manifolds DHX and DHY the requirement of the busy channel assignment for example, could be used in the switching network to beseitigen.Auch the time switching function the control center is carried out by that incoming data characters by means of using a ^lf forward "-Übertragungsadresse to the However, it is equally possible to use the reverse process of storing data characters in the channel's own string memory location and extracting the data characters during the time gap of the connected channel.

Finally, there is access to the input and output switch buses in pairs using individual crossing point addresses in the string storage locations, however, under certain circumstances it can be of It may be advantageous to have access to the bus lines with separate input and output addresses.

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Claims (2)

Claims ^r yl data switching center for serving subscriber stations with several data transmission speed categories in alternating traffic, each subscriber station being served by a corresponding discrete incoming and outgoing time division multiplex channel, characterized in that a time division multiplex channel switching network is provided which has a number of incoming bus lines and an equal number of outgoing lines Contains bus lines, which are arranged in pairs so that each pair of corresponding incoming and outgoing channels of a group of subscriber stations with the same data transmission rate category in the same synchronous, character interleaved multiplex time gap sequence, with several time switching cords are provided for each data transmission rate category, each of which is several Time switch cord storage locations, and that each subscriber station, which is from the central office is served, is assigned exclusively in a selected manner to a corresponding time switching cord storage space provided for a data transmission rate category at all times regardless of the operating state of the subscriber station. 2. Data switching center according to claim 1, characterized characterized in that each time switch cord storage location contains a line status section, and that each time switch has means for detecting the occurrence of a network alert is provided. 309Ö3a / 10U 3- data switching center according to claim 1 or 2, characterized characterized in that each time switch string storage location a character storage section, and that means for writing generated at the center Agitation indicators are provided in the data storage section are. ^. Data switching center according to one of Claims 1 to 3, characterized in that the incoming and outgoing buses terminate at a through-connection network (Each time ^ determination string memory space a memory section for a switching network control address that means for scanning the memory locations of a Cord synchronized with the appearance times of the time division multiplex channel on the incoming busbars of the corresponding Data transmission speed category are provided, and that the through-network control address containing memory section is arranged in such a way that it matches the identity of the incoming Manifold is programmable on which the channel occurs that belongs to the subscriber station currently allocated storage space to the corresponding string is. '. 30983Ö / 10U