GB2171878A - Multiservice multiline machine for information transmission by telephone - Google Patents

Abstract

Multiline, multiservice machine for the transmission of information by telephone. The machine comprises a memory 90 subdivided into areas ZM1, ZM2, ... each of which corresponds to a message. Interface circuits 84 decode an incoming dialled number which corresponds to a desired message service and address the appropriate memory area. Thus, each message can be transmitted on any one of the total of lines. Application to the transmission of information by telephone (results of horse races, stock exchange rates, weather forecasts, games of chance, etc). <IMAGE>

Description

SPECIFICATION Meltiservicernultillre- machinefor information transmission Mrtelephone missfon bytelephone The present invention relates to a machine permitting the transmission of information by telephone.

This information can cover widely differing fields, such as meteorology, the stock exchange, the results of races, sports, games of chance and the like.

A known system making it possible to transmit information over a telephone system is shown in fig 1.

It comprises a telephone exchange 10connected on the one hand to a telephone network 20 and on the otherto in this case three information transmission machines MD1, MD2 and MD3. The connection between the exchange and the machines is provided by groups of telephone lines. The first group has N1 lines,thesecond N2andthethird N3.

In such a system, each machine is allocated to a particularservice. Machine MD1 is allocated to a service S1, relating e.g. to the results of horse races.

Machine MD2 isallocatedto a service S2 dealing e.g.

with weatherforecasts. Machine MD3 is allocated to a service S3, which e.g. gives stock exchange rates.

The structure of such machines (sometimes called static diffusers as opposed to dynamic systems involving the winding off oftapes) is shown in fig 2.

Such a machine MD comprises interface circuit 31, 32, 33, etc connected to the telephone lines N ofthe associated group (whereby an interface card may possibly receive more than one line), a clock40, a storage block 42 and a bus 44. The function ofthe interface circuits isto provide a connection between bus44and lines N, i.e. essentiallytoconnectthe calling line to the bus and to convert into analogue form the digital data supplied by it The function of clock 40 isto time the reading operations ofthe memory and synchronize the connection of a line with the bus atthe time when reading ofthe message starts, as will become more apparent hereinafter.

In practice, the interface circuits are constituted by cards containing appropriate electronic circuits, speci finally a digital-analogue converter, a counter and various line matching circuits (transformer) on a permanent basis. The information contained in the memory is cyclically read. The avoid a calling subscribertaking a message which is being transmitted making it necessaryfor him, after receiving the end of the message, to take up a new transmission to receive the start of the message, the information contained in the memory are organised into relativelyshortgroups called "pages", each page being read in afew seconds, e.g. 8 seconds. All the pages are permanently cyclically read. When a subscriber calls, his call generally arrives when the first page is beingtransmit ted.The connection of this subscriberto the bus is then delayed until the instant at which the first page is again retransmitted, so that in practice the subscriber continuqesto ring. As a page is read in only a few seconds, the wait is short (on average 4 s and atthe worst 8 in the example of a page read in 8s).

Interface cards 31,32 etcfulfill this waiting function and then of connecting atthe desired time. when the first page has been supplied to the subscriber, the cards then connects the line to the address of the bus supplyingthesecond page and so on uptothe last page.

Although such a machine is satisfactory in certain respects, it still suffers from the disadvantage that in a high demand period,traffic can reach saturation point, so that there is a loss of transmitted information and consequentlythe service supplier suffers a profit loss.

In orderto provide a betterunderstanding of this phenomenon, it is possible to imagine an information transmission system comprising three machines (as in fig 1 ), the first MD1 transmitting a first message M1 and having an information flow capacity of 10 Erlangs (E), the second MD2 processing a second message M2 with aflowcapacityof20Eandthethird MD3 transmitting a message M3 with a capacity of 1 OE.

These various capacities are obviously determined by the numbers N1, N2 and N3 of lines allocated to each machine.

The following table I describes a situation in which the requestforinformation, expressed in Erlangs, develops over the hours ofthe day. It can be seen that at hours 4,5 and 6 message M1 cannot be transmitted by machine MD1 to all requesting subscribers, because demand exceeds flow capacity. Thus, there is a loss equal to the difference between the demand and the maximum capacity, i.e. respectively 5,10 and 5E.

The same phenomenon occurs for messages M2 and M3 at differenttimes, becausethe peak hours are obviously dependent on the nature ofthe messages (e.g. the demand forthe results of horse races is obviously very great during thetimefollowing the races, whereas in the case ofweatherforecaststhe demand is more widely spread out).

The final line oftable I also givesthe information loss suffered by the system grouping the three machines. In the present example, the total loss is 60E forthe day.

Naturally, in orderto regulatetbis difficulty, itwould be possibleto conceivea machine in which the groups oflineswould be modified as a function of the traffic.

However, as this change would affectthe connection with the telephone exchange, itwould take a certain time (a few hours or even days). Therefore this solution is not realistic because it is not possible to immediatelyfollowthe development ofthetraffic. TABLE I

MACHINE1MESSAGEI CAPACITY (E t DEMAND MD1 M1 tO 1 5 10 15 20 15 10 5 1 M1)2 M2 20 25 30 25 20 10 15 20 25 30 MD3 M3 10 1Q 5 1 1 2 8-10 15 10 HOURS 1 2 3 4 5 6 7 8 9 SYSTEM LOSSES 5 10 5 5 10 5 -- 10 10 The object ofthe present invention is to obviate this disadvantage.To this end, it proposes a machine having no saturation risk, or which at least consider ably postpones its appearance threshold. This result is obtained through a new organisation ofthe system, accordingtowhich no longer is a machine with its group of lines allocated to a particular service and instead within the same machine are integrated several differentservices,the notion ofthe group of lines allocated to a particularservice disappearing and being replaced buy a subdivision ofthe lines between different services.In this way, when demand is high on one service and low on the others (which is the case in practice, as stated herein before, the peaks are not superimposed for the different services) said service could benefit from a greater number of lines, thereby preventing saturation and increasing by the same amountthe information flow capacity.

lntheexampleoftablel,theflowcapacityofthe total three machines system is 10+20+10=40E.The equivalent machine according tothe invention would have a flow capacity of 40E, but said capacity would be usable for any one of the th ree messages which it is able to transmit. Thus, at hour f, th e 25E necessary for satisfying the demand for message M2 could be supplied, because the demand forthe two other messagesamountsto 11, i.e. in all 25+11 =36E, which is below the system saturation. In the same way,forhour5when the 20Efor message M1 could be supplied, the demand for the two other messages is only 12, which represents a total of 20+1 2=32E.

Thefollowing table 11 gives the differentdata. If demand is high for several messages, as is the case at hours8 and 9, a saturation situation could occur. For exampleathour8, thetotal demand (5+25+15=45E) cannot be satisfied and there would be a 5E loss, whilst at hour 9 the loss would be 1 E. Thus, a system according to the invention would lead to a total loss forthe day of 5+1 =6E, compared with the 60E lost with the prior art machine.

TABLE 11

TOTAL 36 40 36 36 0 32 38 40 45 DEMAND 0 3o23o8os4 LOSSES 0 0 0 0 0 HOURS 1 2 3 4 5 6 7 8 9 This new concept naturally presupposes a mod ification of the functions ofthe constituent parts ofthe machine.In particular, the line interface circuit must be able to carry out a selection as a function of the number called, so that the subscriber having access to the machine according to the invention does indeed receive the expected message from among the several messages which can be transmitted by said machine. This selection function on arrival did not exist in the prior art machines because, as has been made apparent by the description offigs 1 and 2, each machine was allocated to a single message type and was only connected to subscribers requiring this particular message. The selection was made by the telephone exchange (lOin fig 1).

The second modification relates to the memory, which must be able to contain all the messages wh ich can be transmitted. These messages, which are still organized in pages for reasons referred to herein be fore, are stored in order at special addresses. For example, the first message Mi is located between an address a1 and an address a2, the second message M2 is between address a2 and address a3, whilstthe third message M3 is between address a3 and address a4.One of the essential functions ofthe line interface circuit according to the invention is consequentlyto decodethe subscriber's numberand calcuiatethe address ofthe message corresponding to the number called. Dueto the factthatthe memory only contained a single message,this function was not fulfilled in the prior art machines.

Thus, in the machine according to the invention, there is a correspondence table between the called numbers and 4 he memory areas in which are stored the various messages M1, M2, M3 etc. Generally only thefourfinal digitsofthecalled numberare determinative whereas the preceding digits (called BPO in the present French dialing plan) are not in this respect and refer only two the particulartelephone exchange. For example, if a subscriber dials 369.11.1 1,the BPCigroup (in this case,369) enables the call to be addressed to the machine according to the invention and thefourfinal digits 11.11 when decoded bythe line interface ofthe machine, will make it possible to link the calling line with the appropriate memory area.

Such an organisation is able to greatly facilitate the transmission of information, particularly in the case ofvery high demands during limited periods. This is, for example, the case with information relating to the results of games of chance, such as LOTO, demand being very high in the period following each draw and then drops to a low, or even zero value during the following days. A prior art machine serving to transmitsuch results would consequently have to be linked with a very large group of lines to be able to satisfythe very high demand peaks. However,these lines would be very poorly used forthe remainder of the time.This is one ofthe reasons why such a service is not provided by the present information transmission machines,whilstthis snag is obviated by present invention.

In otherwords,the machine according to the invention functionally behaves like a telephone exchange ofthetype found in certain large com panieswherethe actual telephonesare directly accessible from the outside by dialing a BPO common to all the telephones, followed byfourdigits MCDU defining the various telephones. In the machine according to the invention, it is a question of memory areas and nottelephones.

Whereas the machines according to the prior art where ofthe uniservice type, the improvements described herein before make the machine according totheinvention of the multiservicetype. Moreover, as the machirieis no longer allocated to a group of lines exclusively reserved forthetransmission of a given service,the machine can also be called multiline.

The invention is described in greater detail hereinafter relative to non-limitative embodiments and with referenceto the attached drawings, wherein show: Fig. 1, already described, a prior art system.

Fig 2, already described, a prior art information transmission machine.

Fig 3,the general organisationofasystem using a machine according to the invention.

Fig 4, a block diagram of a machine according to the invention.

Fig 5, an embodiment in which certain circuits are grouped.

The system shown in fig 3 comprises a telephone exchange 50 connected on the one hand to the telephone system 55 and on the otherto telephone line 60 (e.g. 250 lines). The machine 70 according to the invention is connected to these lines. On referring to the already described fig 1, the difference as compared with the prior art is immediately clear. No longer are there several machines allocated to different services and working with groups of specific lines and insteadthere is a single multiservice, multiline machine.

The architecture of machine 70 is illustrated in fig 4.

As shown, the machine comprises a certain number of parallel line interface circuits 80,80' 82' etc, which are connected to lines 60. In the illustrated example and in accordance with a standard construction, these lines consist oftwo lines a and b, a TRON line and a RON line. Lines a and b carrythe analogue speech signals and the TRON-RON linesthe standard telephone codes (dialing, picking up the receiver, replacing the receiver, etc). Any random code can be used (e.g. the MF Socotel code).

Each interface circuit comprises a data conversion and line matching interface circuit 82, which is connected to lines a and b, an address calculating and number decoding circuit84, which is connected to the RON-TRON lines and a memory reading sequencer 86, which is connected to circuit 84.

The represented machine also comprises a single memory 90, which is broken down into the same number of memory areas ZM1, ZM2, etc as there are services to be processed S1, S2, etc. Each area contains one message M1, M2, etc and said message is split into pages. This memory is connected to the interface circuits 80 by a bus, which can be split up into an address bus 92 and a data bus 94. More specifically, address bus 92 is connected to sequencer 86 and the data bus 94 is connected to circuit 82.

The machine also comprises a control console 94 connected to the circuit 84 of each line interface circuit. Finally, a clock 98 times the reading into memory 90 and the operation of the interface circuits 80.

The machine operates as follows. The called number MCDU is received in circuit 84 which, via console 95, is aware ofthe correspondence table between on the one handthe differentfour digit number belonging to the variousservices offered and on the other hand the memory areas in which are storedthe messages corresponding totheseser- vices.Thus, the circuit 84 establishes the link between the called number (e.g. 11.11) and one ofthe memory areas, which is designated by a start address (aj) and a finish address (aj).This memory area having been designated, the sequencer addresses this area by address bus 92.The digital data read are extracted from the memory by data bus 94 and reach circuit 82, where they are converted into analogue form and the corresponding signals are supplied to the conductors a and b ofthe line.

Clock98 times the reading ofthe memory and, as in the prior art, makes it possible to determine the appropriate connection timefora linetothe bus. This time is the time ofthe start of reading of the first page ofthe chosen message. Thefunction of the sequencer is consequently to supply address aj, which determines the message selected and the message finish address ai. The addresses ofthe various pages of the message are then ofform a1+n with n ranging between 1 and aj-aj.

The writing ofthe messages into the memory is obtained by conventional not shown means, because they do notform part of the actual machine.The essential point is to keep trace of the addresses of the areas where each message is recorded and this function is fu If i 11 ed by console 95. For each message change, the new addresses are supplied tothe address calculation circuit 84.

Functionally circuits 84 are in each case connected to one line and can be physically grouped. Technicallythis means that several lines use the microprocessor. Fig gives the architecture of thins configuration.

Thus,fortechnical reasons, the analysis of the signals from several RON-TRON lines can be grouped on the same card, sothatthisfunction can e.g. be carried out by a common microprocessor.

Thus, with the structure according to the invention, a line is not allocated to a given service and consequently, for each service, the line potential is equal to all the lines present. This potential is divided up between the various services as a function ofthe instantaneous demands.

Naturally, the invention is not limited to the use of TRON-RON conductors, said embodiment only having been described in exemplified manner. Any telephone line can be used. In the same way, any bus is possible (time or space-time) between interface circuit 80 and memory 90.

Claims (2)

1. A machinefortransmitting information by telephone, wherein it comprises a memory having several areas, containing digital data forming messages, each area storing a message corresponding to a particular service and each message being divided into pages, said memory being associated with an address bus and a data bus, parallel-connected interface- flne circuits, which are inserted between the telephone lines and the buses of the memory, each interface- line circuitfunctionally comprising: a) a first circuit connected between a data bus and line, which ensures matching tothe corresponding line and a conversion into analogue form of the digital data from the bus, b) a second number decoding and address calculating circuit, which is connected to a telephone line, from where it receives a subscriber's number and supplies as afunction ofthe number received, an address of one of the memory areas, whereby said circuit can be common to several interfaces- lines, c) a sequencer connected to the second circuit and to the address bus, a control console connected to the various decoding circuits and giving to said circuitthe correspondence between the differentmemoryareas and the different subscriber's numbers

2. A machinefortransmitting information by telephone, substantially as described herein with reference to Figs 3 to 5 ofthe accompanying drawings.