BE873791A - TIME-DIVIDED TELEPHONE SWITCHING SYSTEM - Google Patents

Description

       

  The present invention relates to a time division telephone switching system.

  
 <EMI ID = 1.1>

  
time division is typically designed to exchange multiplexed signals which are transmitted over multiple input multiple lines on a time division basis with channels

  
or time slices of multiple multiple output lines. Such a time division telephone exchange is described, for example, in "Tho Bell System Technical Journal", volume 56, N [deg.] 7, 1977. The telephone switching system

  
division in time described in this publication is constructed as illustrated in Figure 1 of the accompanying drawings.

  
In summary, it comprises a trunk circuit 1 which receives and

  
 <EMI ID = 2.1>

  
while transmitting call signals or associated signals

  
at one channel, a CODEC circuit 3 which converts the analog signals transmitted by the trunk circuit 1 into time division multiplexed digital signals, as well as a synchronization circuit 4 which receives and transmits the multiplex signals

  
 <EMI ID = 3.1>

  
separating parts of the signals including the recording signal and the call signal, to then transmit these separated parts. The function of the synchronization circuit 4 is

  
 <EMI ID = 4.1>

  
time distribution transmitted over the digital line to the

  
 <EMI ID = 5.1>

  
time division, while multiplexing and demultiplexing to match the multiplicity of the time division of the central office with the multiplicity of the digital line. This telephone switching system

  
time division also includes time division switching networks 6a and 6b for active mode and standby mode which are connected to CODEC circuit 3 and synchronization circuit 4 via switches 7a and 7b respectively, as well as course control devices

  
conversation 8a and 8b for active mode and standby mode, these devices controlling trunk circuit 1, circuit

  
 <EMI ID = 6.1>

  
partition in time 6a and 6b. The conversation route control devices 8a and 8b are connected to the trunk circuit 1, to the synchronization circuit 4 and to the networks of

  
 <EMI ID = 7.1>

  
units 9, 10 and 11. Central processing units 12a and 12b for the active mode and the standby mode are connected to the conversation route control devices 8a and 8b via a switch 13 in order to control all the elements of circuits via these devices 8a and 8b.

  
The time division telephone switching system described above receives a call signal transmitted on the voice frequency line 2 by the trunk circuit 1 which transmits the discrimination signal of a recording signal.

  
 <EMI ID = 8.1>

  
of active mode conversation route 8a via switch 9. The voice frequency signal received by trunk circuit 1 is transmitted to CODEC circuit 3 where it is coupled in a time division multiplicity (comprising the frequency coincidence and phase) which matches

  
 <EMI ID = 9.1>

  
tion in time in the CODEC circuit 3, to then be applied to the time division switching network 6a for the active mode. Under the control of the central processing unit 12a, the conversation route control device 8a controls the time division switching network

  
 <EMI ID = 10.1> of a call waiting signal to transfer the assigned time division multiplexed voice signals. trans-

  
 <EMI ID = 11.1>

  
the numbering registration signal.

  
On the time slot containing the recording signal and the call signal resulting from the time division multiplexing, the signal transmitted via the digital line S is separated by the synchronization circuit 4 and the time slot signal separated is applied to the path control device

  
 <EMI ID = 12.1>

  
recording and the call signal by evaluating the signal output from the synchronization circuit 4 to control the time division switching network 6a under the control of the central processing unit 12a, thereby transferring the signal

  
 <EMI ID = 13.1>

  
assigned to the respective time slots, time slots designated by the recording signal.

  
When a fault occurs in either of the

  
 <EMI ID = 14.1>

  
in time 6a, the conversation route control equipment 8a and the central processing unit 12a, a fault monitoring circuit (not shown) triggers one of the corresponding switches 7a, 7b, 9, 10, 11 and 13 to proceed

  
 <EMI ID = 15.1>

  
attempted.

  
The switching operation described above is also performed between the voice frequency line 2 and the digital line S.

  
 <EMI ID = 16.1>

  
described above, given that the call signal sent on the voice frequency line 2 is transmitted and received by the trunk circuit 1 and given that the call signal sent on <EMI ID = 17.1>

  
Inization 4, the transmission and reception of these two signals, as well as of the various control signals, are treated differently, so that the control process is extremely complicated and it is necessary to install a very large number of control lines. signals between the many circuits and units. Consequently, when it is desired to extend or reduce the telephone network

  
 <EMI ID = 18.1>

  
it is necessary not only to reorganize a large number of order lines, but also to change various order processes.

  
Accordingly, the main object of the present invention is to provide an improved time division telephone switching system capable of easily and economically increasing or reducing the capacity of the switching network.

  
Another object of the present invention is to provide

  
 <EMI ID = 19.1>

  
sophisticated device that can constitute not only the hardware, but also the software that is used to control the conversation path in the form of modules.

  
Yet another object of the present invention is to provide a time division telephone switching system which enables the amount of work to be reduced, as well as the programming operations not only in the event of faults, but also during the extension. of a network.

  
Another object of the present invention is to provide

  
 <EMI ID = 20.1>

  
simplified to reduce the number of elements such as a junction switch holding memory device, as well as the number of commands performed by these elements.

  
Another object of the present invention is to provide a time division telephone switching system making it possible to prevent an outage of the whole system in the event of a double or triple fault.

  
Yet another object of the present invention is to

  
 <EMI ID = 21.1>

  
tion in time capable of economically increasing the capacity of the time division conversation network.

  
According to the present invention, the aforementioned objects, as well as others, can be achieved by digitally processing

  
transmission and reception of call signals in and out of the divisional telephone switching system in the

  
 <EMI ID = 22.1>

  
combining the latter, the timer and the talk route control equipment into a talk route unit of defined capacity. The Conversation Journey Unit

  
 <EMI ID = 23.1>

  
According to the present invention, these and other objects can be achieved by means of a multiplex telephone switching system. by time division comprising several conversation path units, a junction switching unit for interconnecting these different units, a central processing unit intended to ensure general control of the conversation path units, each of the latter comprising a timer for the exchange of a time division multiplex6 signal, a digital trunk circuit des-

  
 <EMI ID = 24.1>

  
recording signal identification and line on state, as well as talk path control equipment connected to receive and transmit a control signal between the timer, digital trunk, and central control unit processing, the trunk switching unit establishing and re-establishing connections between the respective talk path units by processing plural time slots as a group.

  
Other objects, advantages and arrangements of the invention will be better understood on reading the detailed description below, with reference to the appended drawings in which:
Fig. 1 is a block diagram illustrating an example of a prior art time division telephone switching system; Figure 2 is a block diagram illustrating an <EMI ID = 25.1>

  
distribution in time according to the present invention; Figure 3 is a block diagram illustrating the detailed construction of the conversation path unit shown in Figure 2; Figure 4 is a block diagram useful in explaining the switching operation of the telephone switching system using the talk path unit illus- <EMI ID = 26.1> Figure 5 is a circuit diagram illustrating the connections between M conversation path units and a trunk switching unit; FIG. 6 is a circuit diagram of the circuit illustrated in FIG. S, where M 4; FIG. 7 is a circuit diagram of the illustrated circuit <EMI ID = 27.1> FIG. 8 is a circuit diagram of a switch for explaining the redundant behavior of the latter;

  
Figures 9A and 9B are assembly diagrams for

  
 <EMI ID = 28.1>

  
in figure 8; Figure 10 is a block diagram illustrating an <EMI ID = 29.1>

  
a fault monitoring device is incorporated; Fig. 11 is a block diagram useful in explaining redundant switching behavior and the operation of the trunk switching unit; Fig. 12 is a circuit diagram illustrating a modified embodiment of the present invention, in which the voice frequency call signals are transmitted; Fig. 13 is a block diagram illustrating a still further embodiment of the invention, in which processing units are distributed among speech path units, trunk switching units, etc .; Fig. 14 is a block diagram illustrating the detailed construction of the timer;

   Fig. 15 is a block diagram illustrating a further modification of the invention, in which the buffer memory shown in Fig. 14 is further subdivided; Fig. 16 is a timing diagram useful in explaining the operation of the modular timer shown in Fig. 15; Figure 17 is a block diagram illustrating a modification of the system shown in Figure 15; Figure 18 is a block diagram illustrating yet another modification of the system shown in Figure 15; Fig. 19 is a circuit diagram in which two-stage timers are realized by subdividing the memory shown in Figs. 15 and 18;

  
Figures 20, 21, 22 and 23 are assembly diagrams respectively illustrating different modifications of the system shown in Figure 19;

  
Figures 24A and 24B are circuit diagrams useful in explaining how to reduce the number of memories

  
 <EMI ID = 30.1> Figure 25 is a block diagram useful for explaining in detail the construction of the system shown in Figure 24B; Figure 26 is a circuit diagram useful in explaining the operation of the system illustrated in Figure 25; and FIG. 27 is a block diagram illustrating a modification of the system shown in FIG. 25, incorporating a paired control.

   Fig. 2 is a block diagram illustrating the basic construction of the time division telephone switching system according to the present invention, this system comprising active mode talk path units 20a - 20n, a talk route unit of 20a - 20n. 20x standby mode, the 20a - 20n and 20x units being integrated into a unit having a predetermined switching capacity, a test unit 21 for checking the 20a - 20n and 20x talk path units, transfer switches entrance
22a - 22n provided respectively at the crossings between the multiple input lines 23a of the respective talk path units 20a - 20n and the multiple input maintenance line
24a connected between the test unit 21 and the conversation path unit 20x,

   output transfer switches 25a -
25n provided at the respective crossings between the multiple output line 23b of the respective conversation path units
20a - 20n and the multiple output maintenance line 24b extending between the 20x talk path unit and the test unit
21, standby mode and active mode trunk switches 26a and
26x connected as a unit for a number of time slots between the conversation path units 20a - 20n

  
via multiple trunk lines 27a and 27b, as well as a central processing unit 28 emitting a control signal via a bus line 29 to control all of the conversation path units 20a - 20n and 20x, the unit d 'test 21, as well as the junction switching units 26a and 26b, the analysis of the various data at the time of the fault and the test, as well as the transfer instructions for the input and output transfer switches 22a - 22n and 2Sa - 25n via the unit

  
maintenance signal distribution 28a which triggers the aforementioned transfer switches under the control of the central processing unit 28. Although each of the multiple input and output lines 23a and 23b is represented by one line single, in reality, it comprises several lines acting in the manner of a multiple line to transmit digital signals multiplexed by division in time.

  
Thus, these multiple input and output lines 23a and 23b are connected to several CODEC circuits 3 and to several synchronization circuits 4. It is understood that the time division multiplexed digital signal contains the control information. multiplexes required to perform

  
connection of the exchange of the recording signal and the call signal in addition to the voice signal (allocated, for example, to reserve time slots).

  
In the time division telephone switching system implemented as described above, the digitized voice signal transmitted on the multiple input line

  
 <EMI ID = 31.1>

  
the conversation path units 20a - 20n and by the junction switching unit 26a under the control of the central processing unit 28, after which it is transmitted to a CODEC circuit or a synchronization circuit (not shown) via the multiple output line 23b. As will be described in detail below, <EMI ID = 32.1>

  
elements intended to analyze and identify these call signals and these digitized control signals, so that the conversation path unit and the junction switching unit provide control for a switching operation ordinary to repair -

  
 <EMI ID = 33.1>

  
ment 28 must only ensure the control of all the conversation path units 20a - 20n and 20x.

  
Therefore, even if we increase or decrease the number of conversation path units in the manner of a ** function block structure, it suffices to modify the unit Increment

  
 <EMI ID = 34.1>

  
for the analysis and processing of control signals such as

  
the recording signal and the call signal, is distributed among the different conversation path units.

  
When a fault occurs in the conversation path unit 20a, for example, in response to a fault detection signal from a conventional monitoring circuit (not shown), the central processing unit 28 controls, via the maintenance signal distribution unit 28a, the input and output transfer switches 22a and 25a, so

  
to exchange the conversation path unit 20a with the unit

  
20x reserve conversation path. Then, the telephone switching operation is continued using the 20x conversation path unit. As a result of the transfer operation of the input and output transfer switches 22a and
25a, the multiple inlet and outlet maintenance lines 24a and 24b which

  
 <EMI ID = 35.1>

  
reserve talk path 20x, could be connected to the faulty talk path unit 20a. The test unit 21 can then check the conversation path unit 20a which has been disconnected from the main switching system <EMI ID = 36.1>

  
The status of the test is transmitted to the central processing unit 28 via the control signal bus line. Having thus described the construction and operation of the block diagram of Fig. 2, the construction of the talk path units 20a - 20n and 20x will be described in detail hereinafter. FIG. 3 illustrates in detail the conversation path unit 20 shown in FIG. 2, the corresponding elements therein designated by the same reference numerals. In figure 3, the numbers 30a and 30b denote equipment of <EMI ID = 37.1>

  
forward and reverse times connected to the input transfer switches 22 and to the output transfer switches 25 respectively, the digits 31a and 31b designating timers respectively connected to these course connection equipment

  
 <EMI ID = 38.1>

  
that the number 32 designates a hold memory circuit for controlling the storage or read position
(timing) of timers 31a and 31b. The timers 31a, 31b and the hold memory circuit 32 constitute an equi

  
 <EMI ID = 39.1>

  
The forward time division speech path patch 30a is connected to the input transfer switch 22 to receive the digital signal transmitted on the input multipin 23a and to match the timing with the normalized rhythm pulse of the switching system for performing the time division switching operation. In order to realize the timer 31 with an economical low-speed storage device, the connecting equipment

  
The forward time division conversation path 30a may optionally be designed to perform part of the serial-to-parallel conversion and the multiplex conversion.

  
The timer 31a is designed to receive and store the time division multiplex signals from the forward time division speech path connection equipment 30a, as well as to initiate the timer under the control of the memory circuit. maintenance

  
32. On the other hand, the secondary timer 31b is connected to receive and store the signals from the junction switch 26 for performing the switching operation under the control of the hold store circuit.

  
In general, these timers 31a and 31b function to receive the signals transmitted by the multiple input line and to store the multiplexed signals in the conversation path storage devices comprising several random access memories. When the stored signals are read after being addressed by the hold storage circuit, they are transmitted to the output multiple line.

  
Reference numerals 34a and 34b denote digital trunk circuits which receive and identify (or vice versa) control signals such as registration signal and call signal assigned to spare channels by a multiplex processing technique. digital. The control signals also include signals transmitted between exchanges, for example, a polycyclic signal and a supervisory signal, as well as various tone signals and test signals.

   Reference numeral 35 denotes a conversation route control equipment acting as an interface between the hold memory circuit 32, the digital trunk circuits 34a, 34b and the central processing unit 28 for receiving, distributing and partially preprocessing the control signals, while the numeral 36 designates a trunk transfer switch which selects trunk switch units 26a and 26x shown in Fig. 2.

  
In the conversation path unit 20 carried out

  
as described above, the call signal and the time division multiplexed voice signal and which are carried by the input multiple line 23a, are applied to the divisional speech path connection equipment

  
 <EMI ID = 40.1>

  
22. This equipment 30a receives the digitized signal to match the timing and state with the normalized timing pulse of the switching system that is used when operating the switch.

  
 <EMI ID = 41.1>

  
The forward time division speech path connection device 30a may optionally perform the serial-to-parallel conversion and part of the multiplex switching operation in order to simplify the switching processing. The digital trunk circuit 34a transmits control signals such as the registration signal and the call signal to the forward time division speech path connection equipment 30a under the control of the control equipment. conversation path 35 which transmits information to perform the switching processing in the hold memory circuit 32 under the control of the central processing unit 28. In response to the information exchanged, the hold storage circuit 32 initiates the timer 3the

  
 <EMI ID = 42.1>

  
time, thus exchanging the call signal and the input voice signal. Since the hold memory circuit 32 is well known in the art, it is considered unnecessary to describe its construction and operation here.

  
On the other hand, the digital trunk circuit 34b digitally processes the call signals received from other exchanges via the conversation route connection equipment.

  
 <EMI ID = 43.1> junction switch tee 26a, the timer 31b and the rear time division talk path connection equipment 30b, to then transmit the result of the

  
 <EMI ID = 44.1>

  
the conversation route control unit 35.

  
Figure 4 is a circuit diagram illustrating the inter-exchange call signals between two conversation path units 20a, 20b and the junction switching unit 26a, the elements identical to those of Figures 2 and 3 being designated therein by the same reference numbers.

  
In FIG. 4, a route A represented by dashed lines illustrates the route of a call signal which is transmitted by other exchanges via digital terminal equipment such as the CODEC circuit 3 or the synchronization circuit 4 described. above using a spare time slot specific to multiple line 23a. Route A is used to semi-permanently apply the time slot of a calling signal transmitted over multiple line 23a to digital trunk 34. Now assuming that a calling signal is transmitted to digital trunk circuit 34b via this semi-permanently established signal path, this circuit
34b could receive control signals such as registration signal and call signal, to then transmit

  
 <EMI ID = 45.1>

  
tion 35 which translates and identifies the control signals by itself or under the control of the central processing unit 28

  
 <EMI ID = 46.1>

  
result obtained by triggering the timers 3a and 31b if a connection is to be established between the time slots in the conversation path unit 20a.

  
Thus, when an input signal is applied to an output multiple line enclosing its own talk path unit, the talk path control equipment 35 could receive a call signal through the circuit. digital trunk 34b, so that this equipment 35 triggers the timers 31a and 31b via the hold memory circuit 32 and this, by itself or under the control of the central processing unit 28 in order to connect the input to multiple output line 23b. The call signal for the other exchange is sent by the digital trunk circuit 30a via the semi-permanent route.

  
When it is desired to connect the aforementioned input 3 to a multiple line contained in another, for example, in the conversation route unit 20b, the conversation route control equipment 35 provided in this unit 20b controls the communication circuit. storage 32 of the latter under the control of the central processing unit 28 with a view to establishing a route delimited by broken lines.

  
In response to a control signal from the central processing unit 28, a junction hold memory circuit 37a controls the junction switching unit 26a, so as to establish a semi-permanent connection path between the junction units. conversation route. Although, in the above description, only the reception of the call signal from the multiple line 23a of the talk path unit 20a and the establishment of a one-way talk path is mentioned. from multiple line 23a

  
 <EMI ID = 47.1>

  
of the conversation route unit 20b, it is understood that it is also possible to establish a two-way conversation route.

  
Although the construction and operation of the trunk transfer switch 36 will be described hereinafter, at the present stage of the description, this switch can be regarded as a transit circuit.

  
The digital trunk circuit 34a of the conversation path unit 20a outputs a busy signal which is used when a line is free. As described above, it is possible to transmit this busy signal

  
at any time slot on the multiple output line 23b by connecting the latter to the multiple line 27b by establishing a permanent path through the timer 31a and the junction switching unit 26a.

  
In this case, it is possible to transmit the busy signal only by the conversation route control equipment 35 provided in each conversation route unit 20a, 20b without waiting for the control of the central processing unit 28, thus improving the processing capacity (general efficiency) of the latter. Since the junction between the talk path units is semi-permanently established, the talk path control equipment 35 of each talk path unit 20 can know the type of junction in question and do so easily. pairing, transmitting and receiving signals, tests, etc., in its talk path unit.

   Accordingly, it is possible to realize not only the hardware elements, but also the software in the form of modules. Therefore, when it comes to extending the capacity of a switching network, it suffices to accumulate the units of conversation paths 20 as shown in Figure 2 exactly.

  
 <EMI ID = 48.1>

  
Expansion can be easily performed using the 26x standby mode trunk switch unit and 21 test unit.

  
It is excluded that the different elements illustrated in figure 3 can be integrated into a single block (for example, a unit, a network) when miniaturization and high-speed operation become possible thanks to the progress made in the technique of integrated circuits. With the prior art redundant structure provided for each apparatus, it has been inevitable to increase the number of pieces of hardware required to provide redundant switching of the respective apparatus. However, by performing redundant switching for each unitary structure (conversation path unit) in the manner described above, the above-mentioned defect can be avoided.

  
Fig. 5 illustrates the connection between M speech path units and a trunk switching unit in which timers TSW-F and TSW-B considered to be contained in a single speech path unit are arranged on both sides. another of the junction switching unit for ease of description. In FIG. 5, the junction switching unit consists of N junction switches 40a - 40n having M input and output lines, as well as a junction hold memory circuit 37a.

   Each TSW-F timer comprises a circuit 41 which multiplexes the signals coming from the input multiple line, a conversation path storage device 42 which stores the output signals of the multiplexer circuit 41, as well as a demultiplexer circuit. 43 which distributes the output read signals transmitted by the speech path storage device 42 over N multiple trunk lines. Addressing information for the conversation path memory device 42 is stored in a hold memory circuit 32 (not shown in fi- <EMI ID = 49.1>

  
Each TSW-B timer also includes a multiplexer 41 ',

  
a demultiplexer 43 'and a conversation path storage device 42' operating in the same way as the corresponding elements of each TSW-F timer.

  
 <EMI ID = 50.1>

  
Junction between the multiple junction lines 27a and 27b can be performed automatically by the junction switching unit 26a. In addition, it is possible to minimize
(a) the number of multiple trunk lines extending from a timer by multiplexing multiple trunk lines 27a and
27b on the basis of a time division, thus reducing the number of cables, while facilitating extension work.

  
The optimum number of multiple trunk lines extending from a timer is determined by the speed of the signal transmitted on those lines, the timing tolerance between the talk path unit 20 and the trunk switch unit 26 , as well as the number of trunk switches and the volume of the hardware. This relationship will be described below with reference to a specific example.

  
For the description, we will now assume that the number
(N) of junction switches is 4 and the capacity of

  
the matrix of each of these trunk switches (i.e. the number (M) of multiple trunk lines connected to timers 31a and 31b) is 4 and 8 respectively.

  
Figure 6 illustrates the connection of a system in which M '4. In this case, the connections of the trunk switches 40a - 40d are always fixed as shown by the solid lines. More particularly, it will be assumed that the slip between the input terminal of the junction switch
40a is 0, that of junction switch 40b is 1, that of junction switch 40c is 2, and that of junction switch 40d is 3.

   A slide of 0 means the number of input and output terminals of the junction switch are equal, a slide of 1 means the number of output terminals of the junction switch is equal to the number of input terminals + 1 , a shift of 2 means that the number of output terminals is equal to the number of input terminals &#65533; 2 and a shift of 3 means that the number of output terminals is equal to the number of input terminals 3. In this embodiment, the input and output terminals of the junction switch are symmetrically arranged to perform und command called in pairs, that is to say to command 3 both the TSW-F and TSW-B timers by means of the common hold memory 32.

  
The system described above is referred to as a "perfect pairing configuration", where each trunk switch is balanced there between a TSW-F timer and the other TSW-B timer.

  
 <EMI ID = 51.1>

  
between two timers TSW-F (N [deg.] 1) and TSW-B (N [deg.] 4) increases to the point that a multiple trunk line cannot transmit all of these calls. In this case, the problem of an imbalance in the number of simultaneous calls, can be solved by assigning the simultaneous calls corresponding to certain channels, to the timers of the trunk switch JSW1 carrying, for example, a greater number of calls. simultaneous as shown by the dashed lines.

  
The dimension of the trunk switch matrix is the same as the number of TSW-F and TSW-B timers, i.e. the number of conversation path units, so that this matrix can be easily made with elements of material. If the number of multiple trunk lines connected

  
a timer is 4, in which case the maximum number (M) of 20 talk path units is 16, the total number of multiple trunk lines reaches 128, which is half the name-

  
 <EMI ID = 52.1> figure lOb, pages 60 and 61 of "Communication and Electronics",

  
 <EMI ID = 53.1> previous, the number of 616mcnts of material of the demultiplexer circuit 43 of the primary timer (TSW-F) and of the multiplexer circuit 41 'of the secondary timer (TSW-B). <EMI ID = 54.1>

  
The permanent connection diagram of the JSWa - JSWd trunk switches is the same as that shown in figure 6 and is shown in solid lines. In this respect, the conversation path from timer TSW-F N [deg.] 1 can be connected uni-

  
 <EMI ID = 55.1>

  
JSWa- JSWd trunk switches are modified as shown by the dashed lines. It then becomes possible to establish conversation routes also with the TSW-B N [deg.] 5 - 8 timers. This change of connection can be easily effected by modifying the content of the junction hold memory circuit 37a which is common for trunk switches.

  
As a result, we can establish conver-

  
 <EMI ID = 56.1>

  
by designing the connection diagram of the JSW trunk switch such that half of the channels in a time division multiplex network are connected as indicated by the solid lines, while the channels of the other half are connected, based on a time distribution, as shown by the dashed lines. Also in this case, the number of secondary timer hold storage devices which are controlled in pairs can be reduced by establishing a symmetrical connection diagram for the JSW trunk switches. Just like in

  
the embodiment of FIG. 6 in which M - 4, it is possible to envisage an increase in the number of simultaneous calls between a timer TSW-F and a specific timer TSW-B by partially modifying the connection diagram of the switch. junction, to increase the capacity of the junction switch between specific timers.

  
Although, in the above description, the characteristics and operation of the system have been described with reference to cases where M - 4 and M - 8, other values can be selected for M. In addition, as one will understand it, instead

  
To change the connection diagram of JSW trunking switches according to a single channel unit, the change can be made according to a combined unit of a few channels. several tens of channels depending on the value of M,

  
the setting regarding the probability of internal blocking, the allocation of the multiple line to the timers, the maximum capacity of the conversation path reed, etc. In any case, it is possible to reduce the number of hold memory devices to a fraction or only a few percent compared to the case in which the number of these devices defining the connection diagram of the JSW junction switches varies for each channel.

  
A change in the connection diagram of the trunk switches is necessary not only when an imbalance occurs in the number of simultaneous calls, but also when it is desired to extend the network, just as in conventional telephone exchanges.

  
In this embodiment, the trunk switches are arranged collectively, but they can also be scattered. For example, the pieces of hardware comprising the JSW trunk switches can be distributed among primary or secondary timers. The operating principle of this distribution system is the same as that of a collective system.

  
The construction of the JSW trunk switches is similar to that of a well-known space switch (S), with the exception that the change of the connection diagram is not required for ordinary call handling and the change is carried out on the basis of a set of several

  
 <EMI ID = 57.1>

  
A change in the connection diagram is necessary when it becomes essential to switch to a 20x reserve conversation path unit in the event of a fault in a 20 conversation path unit. As described above, since the change of the connection diagram is carried out according to a set of a few channels to several tens of channels, it is possible to reduce,

  
 <EMI ID = 58.1>

  
in the junction maintenance memory device 37a, thus making it possible to quickly remedy the defect.

  
 <EMI ID = 59.1>

  
Redundant switching behavior of the conversation path unit, i.e. the operation of the input transfer switch TRF and the output transfer switch TRB. More particularly, the input transfer switch TRF consists of two transfer switches U and V whose fixed contacts provided on the opposite sides (upper and lower sides) "are connected to each other. To the fixed contacts au and bv, a multiple input line 23a is connected from the synchronization circuit or from the CODEC circuit, while a multiple maintenance output line 24a from the ossai unit 21 is connected to the fixed contacts bu ot av. The mobile contact eu of the transfer switch U is connected to the equipment

  
 <EMI ID = 60.1>

  
in the time before TDC-F of a conversation path unit via a multiple line 23a, while the mobile contact cv of the transfer switch V is connected to the input transfer switch TRF of the next floor or 8 a 20x standby or standby mode conversation path unit.

  
Likewise, the output transfer switch TRB consists of two transfer switches W and X whose fixed contacts provided on the opposite sides are connected to each other. The fixed contacts bw and ax are connected to the test unit 21 via the multiple maintenance input line 24b, while the fixed contacts aw and bx are connected to a multiple output line 23b going to the synchronization circuit. or

  
to the CODI circuit: C. The mobile contact cw of the transfer switch W is connected to the multiple line 23b leaving from the team.

  
 <EMI ID = 61.1>

  
TRB output transfer tor or a 20x reserve conversation path unit. These input and output transfer switches TRF and TRB are connected in pairs for the respective talk path units and the transfer switch pairs U, V, W and X are transferred by a signal from the central unit. treatment 28 via a feeder signal distributor 28a. These transfer switches can be mechanical or electrical.

  
The operation of the input and output transfer switches TRF and TRB will be described below with reference to FIGS. 2, 9A and 9B.

  
 <EMI ID = 62.1>

  
transfer TRF and TRB shown in Fig. 2 are switched to the "a" side and all talk path units 1 - n are operating normally. Under these conditions, the input transfer switch TRF establishes an interconnection path between the input multiple line 23a and the speech path connection equipment &#65533; time distribution before

  
 <EMI ID = 63.1>

  
interconnection between the test unit 21 and a reserve conversation path unit 20x. The output transfer switch TRB establishes an interconnection path between the backward time division speech path connection equipment TDC-B of the speech path unit and the output multiple line 23b, as well as 'an interconnect path between the reserve talk path unit 20x and the test unit 21. As a result, an interconnection is established between the multiple input and output lines, the CODEC circuit and the circuit. synchronization equipment (not shown), the forward and reverse time division speech path connection equipment TDC-F, TCD-B, the test unit 21 and the uni-

  
 <EMI ID = 64.1>

  
the validity check of the reserve conversation path unit 20x. In FIG. 9, the blocks in hatched lines represent the elements.

  
 <EMI ID = 65.1>

  
When a disturbance occurs, for example, in a conversation path unit 20a and the sides of-

  
 <EMI ID = 66.1>

  
thus switched to contact "b", the front and rear time division speech path connection equipments of the speech path unit 20a are connected to the test unit 21, while the multiple lines of-

  
 <EMI ID = 67.1>

  
20x reserve conversation via multiple maintenance lines 24a and 24b. Thus, the test unit 21 checks the faulty speech path unit 20a to locate the fault by checking the received and transmitted signals or by using other measures, to then transmit the results of this check to the central processing unit.

  
Fig. 10 illustrates a modified embodiment of the digital telephone switching system of the present invention which is designed to rapidly detect faulty equipment and then transfer to spare equipment, thereby continuing the switching operation. The embodiment illustrated in Fig. 10 comprises monitoring equipment 50 and monitoring information lines 51 connecting the latter to the respective talk path units 20a - 20n and 20x.

   When a large and common fault occurs (for example, the fault in the power supply circuit, the timing signal source, and the control information distribution circuit) in the conversation path unit or the call switches. junction 26a and 26b, a signal representing this fault is transmitted to the monitoring equipment 50 via the lines 51. The number of monitoring lines 51 interconnecting the conversation path units <EMI ID = 68.1>

  
Monitoring equipment 50 quickly provides information about the fault to the central processing unit

  
28 depending on the content of the monitoring lines 51. As a convenient means for transmitting information about the trouble from the monitoring equipment 50 to the central processing unit 28, a periodic review operation can be used. by this unit or to a forced interruption by the monitoring equipment 50. The method to be used is determined by considering the required quality of service, its efficiency, etc.

  
The operation of the junction switching unit JSU will be described below with reference to figure 11. It will be recalled that this unit has the function of controlling the junction operation between the TSW timers of several travel units. conversation (SPU). This is how the trunk switching unit is put into operation when the network is to be extended.

  
due to the addition of conversation path units

  
or when a fault occurs in a conversation path unit, or also during a transfer connection of the multiple input and output lines 23a and 23b of a unit

  
specific talk path on the 20x reserve talk path unit. The JSUa trunk switch unit consists of several JSW time division trunk switches (only the JSWa switch shown) and a trunk switch hold memory circuit 37a which generally controls the various trunk switches. JSW time division junction. The system illustrated in Fig. 11 is doubled by providing two systems 26a and 26x made as described above for the trunk switch unit JSU.

  
The transfer operations carried out by the trunk switching unit in the event of a fault are carried out as follows. Consider the case of a transfer operation whereby a signal transmitted on the multiple line 23a (N [deg.] L) of the talk path unit 20a (N [deg.] L) is transferred to the line. multiple 23b (N [deg.] l) and to multiple line 23b (N [deg.] n) of the conversation path units 20a and 20n as indicated by the solid lines.

   Due to the disturbance of the talk path unit 20a when the reserve talk path unit 20x (N [deg.] X) is used to perform the switching operation, under the control of the central unit processing, the states of the transfer switches TRF, TRB and the hold memory circuit 37a of the time division trunk switch JSWa are changed. These state changes are made, under the control of the central processing unit (CPU) to transfer transfer switches

  
 <EMI ID = 69.1>

  
to set the status of the TSW timer and the DTRK digital trunk circuit of the 20x conversation path unit
(N * x) in the same way as that of the control path unit

  
 <EMI ID = 70.1>

  
20x (N * x). As a result, it is possible to ensure a normal transfer operation even when a fault occurs.

  
 <EMI ID = 71.1>

  
TRF transfer switch (N * l), the 37x junction hold memory circuit, the junction transfer switch

  
 <EMI ID = 72.1>

  
set as shown in figure 11 in order to pass a test current from the test unit 21 to the defective conversation path unit 20a (N'1) via a path shown in broken lines in figure 11 , it is possible to locate

  
consequently the disturbance occurring in this conversation path unit 20a and isolating the latter from the line without hampering the normal switching operation.

  
TRJ trunking transfer switch is connected

  
 <EMI ID = 73.1>

  
TSW-B, allowing the selection of a 26a or 26x trunk switching unit by the route control equipment

  
of SPC conversation in each SPU conversation path unit. In this way, since the trunk switch JSWa of the trunk switch unit 26a or the trunk switch JSWx of the trunk switch unit 26x is selectively connected to each speech path unit SPU, it is possible to use independently the junction switch JSW for liana system and stand-alone system, thus preventing fault detection test from adversely influencing the normal system.

  
Since the trunk transfer switch TRJ selects the trunk switch unit 26a or 26x of each talk path unit, even when a fault occurs in the trunk transfer switch TRJ of a talk path unit. specific conversation, this bothers-

  
 <EMI ID = 74.1>

  
that no detrimental effect is exerted on the entire transfer system. If the trunk transfer switches TRJ were collectively mounted in a trunk switch unit, for example, the fault occurring in this trunk transfer switch could affect the entire transfer system, which is obviously detrimental.

  
Figure 12 illustrates yet another modification of the present invention which is particularly suitable in a case where the input and output lines of a time division telephone switching system are not limited.

  
 <EMI ID = 75.1>

  
time, but include lines for the transmission of voice signals and connection signals between exchanges without varying these signals. The system comprises a trunk circuit 55, a CODEC circuit 56, as well as a voice signal transmission line 57. The voice signal comprises a signal exchanged between telephone exchanges, as well as an analog voice signal before its conversion into a signal. digital multiplex, so that

  
the voice signal transmission line 57 cannot be connected directly to the conversation path unit SPU and

  
 <EMI ID = 76.1> used in the classic electrical switching system of the

  
 <EMI ID = 77.1>

  
processing trale 28 via a line 58 to monitor the state of the conversation line (busy or free). In addition to the transmission and reception of the dial pulse in the form of an interrupted or inverted direct current, the trunk circuit supports part of the processing of the various signals transmitted by the central processing unit 28. The CODEC circuit 56 has the function of converting analog voice signals to multiplexed digital signals with the same multiplicity and speed as multiple input and output lines 23a and 23b of each speech path unit. The polycyclic signals interchanged between the exchanges are converted into digital signals by the CODEC circuit S6, to then be transmitted and received in a given conversation path unit via the digital trunk circuit.

  
As described above, by coupling the signal

  
 <EMI ID = 78.1>

  
can efficiently perform the handover operation as in the other embodiments, even when the lines connected to the telephone distribution switching system

  
 <EMI ID = 79.1>

  
Fig. 13 illustrates yet another embodiment of the present invention, in which there are provided processing units corresponding respectively to the conversation path units 20a - 20n, 20x, the test unit 21 and to the switching switching units. junction 26a and 26x, so that the processing relating to the TSW timers provided in the conversation path units 20a - 20n, 20x, as well as the digital trunk circuit DTRK are carried out independently by network processing units 61a - 61n, 61x respectively, while only processing involving multiple 60a networks - 60n, 60x, for example, connection processing between different NW networks, test processing, processing of junction connection diagrams during a extension of the NW network, communication between other units

  
processing units of MWP networks or processing units of trunk switches 65a, 65x, or even system processing units 63, are executed via a bus line 64 extending between the processing units and this, under the control of the processing unit 63 of the system which contains the usual data to which one can possibly refer. The test unit 21 is controlled by a processing unit 66, in the same manner as by the conversation path unit SPU.

  
As described above, the network processing unit 61, the test processing unit 66 and the trunk switch processing unit 65 are distributed among the talk path units. SPU, TSTU test unit and JSU trunk switching units which are components

  
 <EMI ID = 80.1>

  
performed by NWP network processing unit, TSTP test processing unit and switch processing unit

  
 <EMI ID = 81.1>

  
embodiment illustrated in figure S, the number of communications between the respective processing units can be reduced due to the simplicity of the overall construction of the paths

  
conversation and the fact that a change in the connection diagram

  
 <EMI ID = 82.1>

  
NWP buckets in the manner described above, even when several faults occur at the same time, the operation of the entire telephone exchange would not be interrupted, thus ensuring the reliability of the communications network.

  
Although, in the above description and the drawings referred to, multiple lines 23a, 23b, 27a, 27b,
24a. 24b, as well as the voice frequency line 57 have been considered as single lines, in practice these lines are however provided in a number which is determined according to the multiplicity of the signals passing through the multiple lines, the operating speed elements such as the storage devices constituting the TSW timers, the maximum desired capacity of the network, as well as the number of conversation path units.

  
Hereinafter, the timer constituting a conversation path unit SPU will be described in detail. When each telephone channel comprises, for example, 8 bits and eight buffer storage devices storing voice signals are connected in parallel for the purpose of reducing the operating speed of the storage elements used, the speed of access to each of them is reduced to 1/8.

  
Fig. 14 illustrates the construction of the parallel connection timer described above, this timer comprising multiple input and output lines 70a and 70b respectively multiplexed into K channels, a serial-to-parallel converter 71 which converts the transmitted signals on the line

  
 <EMI ID = 83.1>

  
parallel-serial weaver 72 converting the 8-bit parallel signals into signals which are routed to the multiple line of

  
 <EMI ID = 84.1>

  
on the input multiple line 70a, as well as a counter 75. As is known, the signal transmission speed on the input multiple line 70a multiplexed into K channels is K x 64 kb / s in the case of 8-bit pulse code modulated ordinary signals. Thus, for example, when the value of K is equal to 128, the speed of the signal transmitted on the input multiple line 70a is equal to 8.192 Mb / s. The write and read functions of the TSW timer are filled alternately by the counter 75 and the holding memory 32, so as to achieve a timed exchange. When this timer is designed as shown in Fig. 14, since it is possible to reduce the speed of the signal emitted on the multiple line of in-

  
 <EMI ID = 85.1>

  
weight of the signal sent to the storage devices

  
 <EMI ID = 86.1>

  
Hold memory device 32 are repeated alternately and the operating speed of the buffer storage device BM is increased to twice 1.024 Mb / s.

  
According to yet another modification of the present invention, a buffer storage device (for example, that designated by BM, in FIG. 14) is subdivided into several blocks, so as to simultaneously perform the sequential write and read operations for them. different blocks, thus reducing the necessary speed of the buffer storage device to about half that mentioned above. The order of the write and read operations of the buffer storage device may optionally be reversed to perform the read-write operation. In the description below, mention will be made of the two operating modes.

  
Figure 15 illustrates an example of such a timer, the entire system being referred to as "modular timer 95". In this figure, the elements corresponding to those of Figure 14 are designated by the same reference numerals.

  
 <EMI ID = 87.1> M memories obtained by subdividing a storage device

  
 <EMI ID = 88.1>

  
of these blocks comprises a data input terminal Di, a data output terminal Do, an address input terminal Add, a

  
 <EMI ID = 89.1>

  
an inhibition gate, digits 85 and 86, decoders, digit 87, a selector circuit and digits 88 - 90, OR gates, while ATIM denotes a signal indicating the pulse widths of WEp and Rp, this signal is usually applied at a defined period.

  
The operation of the system illustrated in FIG. 15 will now be described, with reference to FIGS. 16A - 16J of which FIG. 16A illustrates the state of an input multiple line 91 connected to a conversation route control unit 71 , T representing the width of a timeslot of this multiple line, while A, B, C, D and E represent

  
the contents of the respective time slots of the multiple input line 91. Fig. 16B shows the contents of the counter.
75, in particular, the counting of the lower rank bits. Fig. 16C illustrates a read / write signal output from decoder 86 as a function of the output of counter 75, R representing a read cycle, while W represents a write cycle. Figure 16D shows the timing of memory access. Figure 16E illustrates the sequential addresses represented by the higher order bits of the output of counter 75, <EMI ID = 90.1>

  
all memory blocks. Figure 16F illustrates a write pulse, while Figure 16G illustrates the processing of memory blocks M1 - M4, the symbols Add: a (A), Add: &#65533; (B) mean- <EMI ID = 91.1 >

  
are A and B respectively. Further, Figure 16H illustrates the waveform of a read pulse, Figure 161 illustrates the waveforms emitted on the multiple output lines

  
 <EMI ID = 92.1>

  
conversation route command 71 is quadruplexed. In this case, the lower order bits corresponding to the output [pound] of counter 75, that is to say log2 L bits (2 bits, given that

  
 <EMI ID = 93.1>

  
output signal obtained is used as a read / write signal (corresponding, in figure 16, to a case where the count of the two bits of lower rank is 4), while the information
(information D in the case of Fig. 16A) of a time slot corresponding to the position R where the output signal of the decoder 86 is "1", are neglected. Then, the time slot is assigned to the play timing (typically, a sequential access timing).

  
The information transmitted on the multi-input line 91 is entered into the memory bank at a position WEp shown in Fig. 16F with the write timing W (W side of the read / write waveform) shown in Fig. 16C , thus selecting the address of the hold memory device 32 by the selector circuit 87. This address is general.

  
 <EMI ID = 94.1>

  
are decoded by decoder 85. In a case where / - 4, the output signal of decoder 85 appears only at one of the four output terminals. This output signal corresponds to a block selection of the respective storage devices. As a result, the read / write signal applied to an input of the

  
 <EMI ID = 95.1>

  
The block of the four memory blocks is designated to enter data into the address assigned above the memory block. This process is illustrated by an arrow in the figures.

  
 <EMI ID = 96.1>

  
that the content of the address becomes "B".

  
A negligible time slot appears, every four time slots as described above, on the information stream transmitted over the input multiple line 71 and which is synchronized with the common timing signal (in fig.

  
 <EMI ID = 97.1>

  
laughter of counter 75 is 4). No write operation is necessary for this negligible time slot (information D shown in FIG. 16A). Since it is decoded by decoder 86 and used as a read timing, this timing position (i.e. the count 4 of the two lower bits of counter 75) is decoded by decoder 86 to get a read / write signal of equal amplitude
(shown in Figure 16C) on its output. When this signal

  
 <EMI ID = 98.1>

  
a side address SQ (P in FIG. 16E) common to the memory blocks M1 - M4, so that an input of the OR gates becomes "1". Therefore, the read signal of the respective memory block becomes "1" (this change not being caused by the output signal of the decoder 85). As a result, the outputs of all memory blocks become effective and, as shown by the arrow going <EMI ID = 99.1>

  
by the read pulse illustrated in figure 16H.

  
Thanks to the operation described above, it is possible

  
 <EMI ID = 100.1>

  
memory blocks with a single read pulse, thus independently applying the read data four multi-line lines

  
 <EMI ID = 101.1>

  
owing to the fact that the access time per length of information unit of the storage device can be reduced by a long

  
 <EMI ID = 102.1>

  
As pointed out above, the information transmitted over the input multiple line is neglected at all time intervals, but without however causing any disturbance for the reason mentioned below.

  
 <EMI ID = 103.1> laughter of the output of the counter 75 provided in the modular timer 95 via a command line 97. The terminal numbers

  
 <EMI ID = 104.1> plexer 96, the output of the latter, that is, the data stream transmitted on the multiple input line 91, selects

  
 <EMI ID = 105.1>

  
multiple entry 91; on the other hand, when the contents of the command line 97 are two, the input terminal 12 is selected,

  
so that the data transmitted on the multiple line 98- of

  
low rank multiplicity appear on the multiple entry line. When the contents of command line 97 are three,

  
 <EMI ID = 106.1>

  
low-ranked city appear on multiple entry line 91 but, when the content of that command line is four,

  
input terminal 14 is selected. Therefore, the data transmitted on the multiple input line 91 has no meaning. As a result, no effective data could be lost, if data such as the time slot on multiple line 91 is neglected. The content of command line 97 consists of the two lower-order bits of

  
the output of the counter 75 provided in the modular timer 95, output which is equivalent to the input information of the decoder 86 of this modular timer 95. Therefore, by matching the output (4 in the example shown in figure 16) of the decoder 86 with the number of the input terminal (14 in the case shown in figure 17) which is not connected a multiple line of the lower rank multiplicity of the multiplexer 96, the time slot can be correlated negligible appearing on multiple input line 91 with a time slot to be neglected (assigned 6 a read timing, more particularly, a sequential access timing).

  
 <EMI ID = 107.1>

  
unit of information and, in order to reduce this number, the number of memory blocks 1 is increased. When spare access timing is required for talk route control, the number of neglected time slots is increased.

  
Although, in the embodiment illustrated in FIG.

  
 <EMI ID = 108.1>

  
the writing rating may possibly be as well. FIG. 18 gives an example illustrating the latter case, in particular a modular timer 95 '. This modification comprises multiple input lines which respectively receive the parallel output of the speech path control equipment 71, a multiple output line 102 transmitting a signal.

  
 <EMI ID = 109.1>

  
ture whose transmission ceases every t time intervals just like the write pulse WEp illustrated in FIG. 16E. WE'p represents a write pulse sent every &#65533; time intervals just like the read pulse Rp shown in Figure 16F. The other reference symbols have the same meanings as in figure 15.

  
 <EMI ID = 110.1> tition in time according to a two-stage construction in which a modular timer such as the one illustrated is used.

  
 <EMI ID = 111.1>

  
are of the same construction as the modular timer 95 shown in Figure 15. Each of these 616 elements includes four dis-

  
 <EMI ID = 112.1>

  
1124 are of the same construction as the modular timer 95 'shown in Figure 18. Each of these elements also includes four Mt - M4 storage devices whose details are not shown. With this construction, since the number of multiple junction lines between the primary and secondary timers is equal to the number of memory blocks of the latter, it is possible to realize the junction between the primary and secondary timers without adding new ones. cir-

  
 <EMI ID = 113.1>

  
illustrated in figure 2 is represented by broken lines so that, theoretically, the junctions are established in the manner illustrated in figure 19.

  
Figure 20 shows another modification of the system <EMI ID = 114.1>

  
M2 is reduced to 1 / N of the number of multiple trunk lines, while a demultiplexer 120 subdividing a multiple line into multiple multiple lines 1211 - 121N is provided outside of the primary timer 110. The multiple subdivided lines are multiplexed into one. single line by a multiplexer 123 provided on the input side of the secondary timer.

  
Figure 21 illustrates a modification of the system shown in Figure 20, in which N groups of blocking circuits <EMI ID = 115.1>

  
output of the primary timer 110. The read pulse Rp illustrated in FIG. 15 is subdivided, by a decoder 131, into N systems connected to the respective blocking circuits. A multiplexer 123 is provided on the input side of the secondary timer 112. With this construction, the operating phase of the multiple trunk line is subdivided &#65533; systems. However, if it is desired to obtain the same phase, a double buffer construction can be adopted, i.e. blocking circuits operating at the same timing can be interposed on

  
the output side of the primary timer. This construction is advantageous for a switching network in which a long trunk cable is used, since the speed of the signal transmitted on the multiple trunk line decreases. Furthermore,

  
 <EMI ID = 116.1> 95 ', the number of multiple trunk lines also increases, so that it becomes possible to connect all modular timers to trunk lines.

  
Figure 22 illustrates yet another modification of the system shown in Figure 20, in which the number of memory blocks is increased to j times the number of trunk lines. In this case, each group of j memory blocks of the

  
 <EMI ID = 117.1>

  
Corresponding demultiplexers 1361, 1362 ..., provided on the input side of the secondary timer 112. The outputs of these de-

  
 <EMI ID = 118.1>

  
tively. This construction makes it possible to reduce the number of multiple junction lines.

  
Figure 23 illustrates yet another modification of the system shown in Figure 22, in which registers at <EMI ID = 119.1>

  
are provided for each group of memory blocks of the primary timer 110. In the secondary timer 112, the signals of

  
 <EMI ID = 120.1>

  
corresponding shift registers 1411, 1412 ... in order to perform a series-parallel conversion. The period of operation of the blocking circuits provided on the access side

  
 <EMI ID = 121.1>

  
random access side, thus ensuring high operating speed. Consequently, when the blocking circuits described above are replaced by shift registers with parallel-to-series or series-to-parallel conversion, it is possible to involve

  
both blocking function and parallel-to-serial or serial-to-parallel conversion function. As a result, serial to parallel conversion can be provided for junction units.
(case in which the junction side is accessible sequentially) or for the transmission side of the line (case in which the transmission side is accessible sequentially) and this, without adding any element.

  
Although in the embodiments described above, in order to provide pairwise control of the primary and secondary timers TSW-F and TSW-B of the path unit

  
conversation, a holding memory device common to these timers is used, paired control is not always essential. Thus, independent storage devices can be used for the respective timers.

  
Figure 24A illustrates yet another modification of the system shown in Figure 19, in which the timers are of the two-stage type. More particularly, on the side of the multiple input line 91 and on the side of the multiple output line 102, storage devices M are provided.
(for example, conversation path memory devices) randomly accessible by devices of <EMI ID = 122.1>

  
on the junction side, the storage devices are accessed sequentially by counters 153. and 154. In order to simplify the description, the primary and secondary timers 110 and 112 are two in number respectively.

  
In this way, when the junction c8té is accessible sequentially by the counters 153 and 154, the content of the planned conversation path storage device M1

  
 <EMI ID = 123.1>

  
calling a common conversation path memory device for the primary and secondary timers as shown in Figure 24B. This system makes it possible to eliminate the counters illustrated in FIG. 24A, so that the number of conversation path storage devices M is reduced by half.

  
Figure 25 is a block diagram illustrating in detail the system of Figure 24B. In Figure 25, each of the m multiple input lines 911 - 91m is multiplexed by n. Likewise, each of my multiple output lines 1021 -
102m is also multiplexed by n. Each of the m devices

  
 <EMI ID = 124.1>

  
words (this capacity can be increased or reduced depending on the number of simultaneous calls and the probability of internal blocking).

  
 <EMI ID = 125.1>

  
operates as a control memory device which designates the memory number and its address when time division multiplex signals reach

  
 <EMI ID = 126.1>

  
of a control storage device which designates the number of a read storage device and its address when a signal is taken from a storage device for transmission to the respective multiple lines 1021 - 102m.

  
Each maintenance memory device has

  
 <EMI ID = 127.1>

  
m

  
memorization. In general, the hold storage device 150 controls the storage devices.

  
 <EMI ID = 128.1>

  
This control process will be described below with reference to Fig. 26. Assume that a line having a number of timeslots a of the input multiple line 91. is to be assumed.

  
 <EMI ID = 129.1>

  
an unoccupied address can be selected by a central device.

  
 <EMI ID = 130.1>

  
multiple line 102.) is established in the same manner using the conversation path memory device

  
 <EMI ID = 131.1>

  
conversion of the conversation path can be n times per unit of information for writing and reading respectively,

  
so that the total number of channels that can be exchanged is n x m.

  
Figure 27 illustrates a paired control system incorporated into the figure 25 or 26 system. In this case, <EMI ID = 132.1>

  
In the usual way, tooth multiple input and output lines using the write addresses and read addresses of the information transmitted to the respective multiple lines. In order to connect the same multiple lines to each other, the data of the speech path memory device is read during the previous half of a time slot and this data is fed into the speech path memory device during the later half of that time frame. Given that

  
the operation of this time division telephone exchange is similar to that of the system illustrated in figure 26, it seems superfluous to give a description.

  
The advantages of the respective embodiments are as follows:

  
 <EMI ID = 133.1>

  
The time of the present invention, the digital time division switched trunk circuit and the talk path control equipment are bundled or integrated for a certain capacity, the trunk connection between the integrated talk path units being provided by a trunk switching unit with a semi-permanent path while, as the network expands, the conversation path units are grouped according to the principle of a functional block structure. Accordingly, the telephone network can be easily extended and the telephone switching system can be easily realized.

  
(2) When transmitting and receiving call signals, they are fed into reserve time slots of multiple input and output lines connected to the switching system using CODEC circuits or circuits synchronization, after which they are applied to a digital trunk circuit via switching units of

  
 <EMI ID = 134.1>

  
establishing permanent routes. Therefore, not only the hardware elements, but also the software of the conversation route control equipment can be implemented as modules.

  
(3) According to the embodiment of the invention which is

  
 <EMI ID = 135.1>

  
in time, the digital trunk circuit, the connection equipment of the call distribution path in

  
the forward and reverse time, as well as the conversation route control equipment for these connection equipments which constitute a time division telephone switching system, are realized as an integral unit, while a unit common reserve is provided for several units. Consequently, when a fault occurs in a unit which is normally put into service, the latter can be switched on smoothly by a transfer switch and a junction switch. For this reason, the working time and the number of programming operations can be reduced not only at the time of fault detection, but also when extending the network.

  
(4) The transfer operation of trunk switches is performed by handling multiple channels as a set or group and this operation is performed only when there is an imbalance in the number of simultaneous calls or when disturbance occurs in the conversation path unit, or when the network has to be extended, but not to order a call. Accordingly, it is possible to reduce the capacity of the storage device used in the junction switch, as well as the control operations performed by the hold storage device, thereby simplifying the construction.

  
(5) Further, as shown in Fig. 13, when a device for controlling the number of simultaneous calls is added. each integral unit of the time division switch, digital trunk circuit, forward and backward time division speech path connection equipment, and speech path control equipment, so as to process simultaneous calls passing through the network by completing a series of simultaneous call commands in each integral unit, it becomes possible to prevent an outage of the entire switching center,

   even when a fault occurs in a specific integral unit and when another integral unit also becomes faulty while the first is switched to a standby unit thus causing a double or triple fault.

  
(b) Regarding the selection of an unused talk channel, since the timers are provided in two stages, it is possible to reduce the number of switching pragrammation steps such as channel alignment.

  
In addition, this two-stage construction of the timers offers advantages in that the capacity to handle the imbalance in the number of simultaneous calls can be increased, while the reorganization of the jumper cables can be simplified at the time of extension. of the telephone network. More particularly, the trunk switches which allow an electrical reconnection of the trunk lines with time division, are arranged between the primary and secondary timers. Consequently, under normal conditions, a specific connection diagram is drawn up; however, when an imbalance occurs in the number of simultaneous calls or when

  
 <EMI ID = 136.1>

  
is changed. This connection solves the problems that arise when two-stage timers are used to build the telephone network. When changing the connection diagram of trunk switches, it is not always necessary to be able to control each channel, but

  
 <EMI ID = 137.1>

  
of a set of channels, thereby reducing the desired bit storage capacity for the trunk switch hold storage device resulting not only in miniaturization of the system, but also in simplification of switching network processing.

  
(7) According to the embodiments illustrated in Figures 13 to 23, since the storage device constituting the timer is subdivided into several blocks, the multiplexing and demultiplexing circuits become superfluous when the memory blocks are in parallel access, thus halving the access time to the storage device.

  
The result is not only a reduction in the conditions required for the cycle time of the storage device, but also a simplification of the peripheral circuits associated with the latter. In addition, when making a simple timer

  
has two stages comprising a simple control algorithm, it

  
It is possible to make junction devices between the primary and secondary timers without adding new circuits.

  
By increasing or reducing the number

  
memory blocks with a predetermined redundancy, the number of junction devices between the primary and secondary timers can be adjusted without increasing the operating speed of the memory device.

  
(8) Further, according to the illustrated embodiments

  
in Figs. 24 to 27, the conversation path storage device provided in a timer is subdivided into several blocks which are arranged in a matrix, so that the multiple input line can have access to the memory blocks.

  
 <EMI ID = 138.1>

  
output can have access to the memory blocks of the same column.

  
Accordingly, the capacity of the timer can be increased without redundant use of the storage device and without increasing the operating speed of the storage device. Therefore, according to the present invention, a time division switching network can be fabricated by using a high capacity timer consisting of an inexpensive storage device suitable for fabrication as an integrated circuit.

  
Accordingly, the capacity of a time division switching network can be easily increased. When it is desired to further increase the capacity of the network, this can be done by combining timers or space switches in many stages.

  
Although the invention has been illustrated and described in

  
Referring to specific embodiments, one skilled in the art will understand that many modifications can of course be made thereto.

CLAIMS

  
 <EMI ID = 139.1>

  
in time in which time division multiplexed signals are exchanged, characterized in that it comprises several speech path units, a junction switching unit ensuring the interconnection between these speech path units, as well as '' a central milking unit

  
 <EMI ID = 140.1>

  
of conversation, each of the latter comprising

  
 <EMI ID = 141.1>

  
predetermined time slots, these signals being distributed over time and multiplexed into several time slots,

  
 <EMI ID = 142.1>

  
a channel, which signal contains a signal identification of

  
 <EMI ID = 143.1>

  
speech path control equipment for receiving and transmitting control signals, this equipment comprising an interface between the time division switches, the digital trunk circuit and the central processing unit

  
processing unit, while the trunk switch unit is designed to establish and re-establish connections between

  
the respective conversation path units by processing multiple time slots as a group.

  
2. Distribution telephone switching system


    

Claims (1)

in time according to claim 1, characterized in that it also comprises a reserve conversation path unit provided in common for the different conversation path units, as well as switching elements intended to replace this call path unit. standby conversation, under the control of the central processing unit, to a conversation path unit normally used when a fault occurs in the latter. <EMI ID = 144.1> in time according to claim 1, characterized in that it also comprises a reserve junction switching unit, as well as elements controlled by the central processing unit to substitute this reserve junction switching unit for the aforementioned junction switching unit when a fault occurs in the latter. 4. Distribution telephone switching system in time, characterized in that each time division talk path unit comprises two timers connected in cascade and between which the trunk switching unit is arranged. S. Distribution telephone switching system in the time in which time division multiplexed signals are exchanged, characterized in that it comprises multiple input and output lines each containing several time slots intended to receive the time division multiplexed signals, multiple conversation path units, one conversation path unit reserve, a trunk switching unit providing the interconnection between the different speech path units and the reserve speech path unit, a test device, a time division speech path unit comprising two changeover switches for branching the connections between the respective speech path units, the reserve speech path unit, multiple input and output lines and the test device, as well as a central unit processing unit ensuring control of all of the speech path units and permutation switches, each of the path units conversation including distribution switches in the time for the exchange of multiplexed signals between predetermined slots, a digital trunk circuit processing a signal associated with a channel, which signal contains a registration signal identification and a line on state, as well as a conversation route control equipment <EMI ID = 145.1> equipment comprising an interface between the time division switches, the digital trunk circuit and the central processing unit, the trunk switching unit being adapted to establish and re-establish connections between the respective speech path units by processing several timeslots as a group, while the changeover switches are controlled by the central processing unit to replace the spare talk path unit, as well as the multiple input and output lines. <EMI ID = 146.1> when a fault occurs in the latter, while connecting the test device to this faulty talk path unit. <EMI ID = 147.1> in time according to claim 5, characterized in that the test device is normally connected to the spare talk path unit via the changeover switches when a normally used talk path unit is functioning correctly, so to confirm this correct operation. <EMI ID = 148.1> in time according to claim 5, characterized in that it <EMI ID = 149.1> the faulty state of the talk path units while, when a fault occurs, the central processing unit trips the changeover switch in response to the output signal from that monitor. 8. Time division telephone switching system in which time division multiplexed signals are exchanged, characterized in that it comprises several speech path units, a trunk switching unit establishing connections between the latter. , as well as a central processing unit ensuring the control of all the conversation path units, each of the latter comprising distributed switches. <EMI ID = 150.1> time partition between predetermined time slots, a digital trunk circuit processing an associated signal <EMI ID = 151.1> line registration and commissioning state, as well as speech path control equipment receiving and transmitting control signals, such equipment comprising an interface between the time division switches, the digital trunk circuit and the A central processing unit, the trunk switching unit being adapted to establish and re-establish connections between the respective speech path units by treating several time slots as a group, while it comprises a call switch. time division junction and a junction hold memory device which controls the junction under the control of the central processing unit. <EMI ID = 152.1> in time according to claim 8, characterized in that the junction switching unit is provided in duplicate. 10. A time division telephone switching system according to claim 8, characterized in that each of the speech path units includes a trunk changeover switch which determines which of its output signals is to be received by the call units. junction, this junction changeover switch being under the control conversation route control equipment. 11. A time division telephone switching system in which time division multiplexed signals are exchanged, characterized in that it comprises several conversation path units, a junction switching unit ensuring the interconnection between them. different conversation path units, a central processing unit intended to control all of the latter, each of the conversation path units comprising time division switches for exchanging the aforesaid signals between predetermined time slots , a circuit <EMI ID = 153.1> channel, a signal which contains a registration signal identification and a line put-into-service state, as well as conversation path control equipment receiving and transmitting control signals, this equipment comprising <EMI ID = 154.1> the digital trunk circuit and the central processing unit, while the ring switching unit;: one is designed to establish and re-establish connections between the respective speech path units by processing several time slots in the form of a group, the system also comprising an additional trunk circuit which monitors a state of conversation of an analog line, transmits and receives a double pulse and takes care of part of the processing of the various signals which are carried out by the central processing unit , as well as elements connected to the output of this additional trunk circuit to convert a voice signal <EMI ID = 155.1> tors distributed over time. <EMI ID = 156.1> in the time in which time division multiplexed signals are exchanged, characterized in that it comprises several speech path units, a junction switching unit ensuring the interconnection between the different speech path units, a central processing unit intended to control all of the latter, each of these conversation path units comprising <EMI ID = 157.1> aforementioned between predetermined time slots, a digital trunk circuit for processing an associated signal <EMI ID = 158.1> line recording and commissioning state, as well as conversation path control equipment receiving and transmitting a control signal, this equipment comprising <EMI ID = 159.1> the digital trunk circuit and the central processing unit, while the trunk switching unit is designed to establish and re-establish connections between the speech channel units by processing several timeslots as a group, the system also comprising control elements for processing in each talk path unit and in each trunk switch unit, while the central processing unit only performs processing involving multiple talk path units, while monitoring the operation of the control elements in each of them. 13. Time division telephone switching system in which time division multiplexed signals are exchanged, characterized in that it comprises several conversation path units, a junction switching unit ensuring the interconnection between these. different talk path units, as well as a central processing unit for controlling all of them, each of the talk channel units comprising time division switches for the exchange of signals between predetermined time slots, a digital trunk circuit for processing a signal associated with a channel, which signal contains a registration signal identification and a line on state, as well as conversation path control equipment receiving and transmitting control signals, this equipment comprising an interface between the time division switches, the digital trunk circuit and the central processing unit, while the unit trunk switch is designed to establish and re-establish connections between talk path units by handling multiple time slots <EMI ID = 160.1> time comprising storage elements intended to momentarily store conversation information at the time of a switching operation, these storage elements being subdivided into several memory blocks, elements for accessing <EMI ID = 161.1> random access of the storage element, as well as elements allowing parallel access to several memory blocks <EMI ID = 162.1> the multiplicity of the multiple line on the random access side as invalid time slots, as well as a random access time corresponding to the invalid time slot as sequential access time, K representing the multiplicity of the multiple line on the random access side, while &#65533; represents the number of memory blocks of the storage element. <EMI ID = 163.1> in time according to claim 13, characterized in that it also comprises a shift register operating according to the serial input / parallel output mode on the sequential access side. 15. A time division telephone switching system according to claim 13, characterized in that the number of blocks of the storage element is variable. 16. A time division telephone switching system according to claim 13, characterized in that part of the invalid time slot is used as reserve access time. <EMI ID = 164.1> in time in which time division multiplexed signals are exchanged, characterized in that it comprises several speech path units, a junction switching unit ensuring the interconnection between these different speech path units, thus a central processing unit intended to control all of these, each of the conversation channel units comprising time division switches for the exchange of signals between predetermined time slots, a digital trunk circuit for processing a signal associated with a channel, which signal contains a registration signal identification and a line-in-service state, as well as speech path control equipment receiving and transmitting control signals, this equipment comprising an interface between the time division switches, the digital trunk circuit and the central processing unit, while the trunk switching unit is designed to establish and re-establish connections between the speech path units by treating several timeslots as a group, the time division switches being made in two stages and comprising memory elements <EMI ID = 165.1> versation at the time of switching, these storage elements being subdivided into several memory blocks, elements <EMI ID = 166.1> as well as elements allowing parallel access to several <EMI ID = 167.1> of the aforementioned multiple lines, the number of memory blocks corresponding to the number of multiple junction lines, while <EMI ID = 168.1> random access side as invalid time slots, thus <EMI ID = 169.1> times not valid as sequential access time, K representing the multiplicity of multiple lines on the random access side, while t represents the number of memory blocks. 18. A time division telephone switching system according to claim 17, characterized in that the number of memory blocks is 1 / N, where N represents the number of multiple trunk lines, this system also comprising a decoder which distributes, among N multiple junction lines, the data read by the aforementioned sequential access, as well as a <EMI ID = 170.1> multiple line on one side where data writing is performed by sequential access. <EMI ID = 171.1> in time according to claim 17, characterized in that the number of memory blocks is 1 / N, where N represents the number of multiple trunk lines, this system also comprising N groups of blocking circuits provided on the side where takes place the <EMI ID = 172.1> <EMI ID = 173.1> N pulses and then apply these to the N groups of blocking circuits, as well as a circuit multiplexing N multiple lines into a single multiple line on a side where the data writing is performed by the sequential access. <EMI ID = 174.1> in time according to claim 17, characterized in that the number of memory blocks is N ', where N' represents the number of multiple junction lines, this system also comprising <EMI ID = 175.1> in a single multiple line on one side where the data is read by the sequential access, as well as a decoder distribute the data among N 'multiple lines on one side where data is written by sequential access. 21. A time division telephone switching system according to claim 17, characterized in that it also comprises a shift register operating in the serial input / parallel output mode on the sequential access side. 22. A time division telephone switching system according to claim 17, characterized in that <EMI ID = 176.1> memory mounts, is variable. 23. A time division telephone switching system according to claim 17, characterized in that part of the invalid time slot is used as reserve access time. 24. Time division multiplex6 telephone switching system in which time division multiplexed signals are exchanged, characterized in that it comprises several conversation path units, a trunk switching unit ensuring the interconnection between these different conversation path units, as well as a central processing unit intended to control all of the latter, each of the conversation channel units comprising a time-division conversation channel unit for the exchange of signals between predetermined time slots, a digital trunk circuit for processing a signal associated with a channel, which signal contains a recording signal identification and a line-on state, as well as a speech path control equipment receiving and transmitting control signals, this equipment comprising an interface between the time division speech channel unit, the digital trunk circuit and the central processing unit, While the trunk switch unit is designed to establish and re-establish connections between the different talk path units using multiple time slots as a group, the time division talk path unit comprising a timer comprising a device <EMI ID = 177.1> momentarily conversation information at the time of a <EMI ID = 178.1> allowing, 1 a multiple input row, to have access to a predetermined address of a memory block belonging to a column of this matrix which corresponds to this multiple input row, as well as elements allowing, If a multiple row Release, <EMI ID = 179.1> holding 1 a column of the matrix that matches 1 this multiple output row. 25. A 2-time division telephone switching system according to claim 24, characterized in that the number of words of each memory block varies by n / m depending on conditions such as the efficiency of use of a multiple line. and the probability of internal blocking of the telephone switching system, n representing the multiplicity of this multiple row, while m represents the number of columns or rows of the matrix. 26. Time division telephone switching system in which time division multiplexed signals are exchanged, characterized in that it comprises several conversation path units, a trunk switching unit ensuring the interconnection between these different units * of conversation paths, as well as a central unit <EMI ID = 180.1> each of the conversation path units comprising time division switches for exchanging the above signals between predetermined time slots, a digital trunk circuit for processing a signal associated with a channel, which signal contains an identification recording signal and a line commissioning state, as well as a speech path control equipment receiving and transmitting control signals, this equipment comprising an interface between the speech channel unit 0 distribution in time, digital trunk and central processing unit, while trunk switching unit is designed to establish and re-establish connections between talk path units by processing multiple time slots as one group, the "time division" talk path unit comprising a timer including a talk path storage device adapted to momentarily store conversation information at the time of a switching operation, said switch device <EMI ID = 181.1> integer greater than 2) intended to control write and read addresses, column and row numbers of a matrix comprising m columns and m rows being attribute * <EMI ID = 182.1> entry ple, to have access to a predetermined address of a memory block belonging to a column of the matrix which corresponds <EMI ID = 183.1> corresponds to this multiple output line, a hold storage device for controlling in the usual way a memory block of the conversation path storage device in order to control a write address, as well as a <EMI ID = 184.1> <EMI ID = 185.1> holding to a row of the matrix which corresponds to the number of the address control storage device, as well as elements intended to assign a read address to a memory block belonging to a column of the matrix which corresponds to the number of the storage device address control, thus allocating an access time of the conversation path storage device to a read operation, followed by an access time allocated to a write operation, these access times occurring at least twice per time frame. <EMI ID = 186.1> in time according to claim 26, characterized in that the number of words of each memory block varies by n / m depending on conditions such as the efficiency of use of the multiple line and the probability of internal blocking of this line multiple, n representing the multiplicity of it, while m