Patent GB-942183-A (GB)
Title: Improvements in or relating to data processing equipment
Inventor: RIDLER DESMOND SYDNEY
IPC: H04M15/38
Filed: 1959-04-08
Abstract: 942,183. Telegraphy; automatic exchange systems. STANDARD TELEPHONES & CABLES Ltd. April 1, 1960 [July 17, 1961], No. 11822/59. Headings H4K and H4P. [Also in Division G4] The address of a word in readonly store PS is derived in part (a) from the input to a " functional block " and in part (b) from an address in a temporary store TS which is allotted to the functional block; the word thus selected from PS contains at least one part (A) which is written into TS at the address just accessed and an instruction part (I) which is applied to the functional block as an output. The read-only store may be a specially wired magnetic core store or a photographic store; the temporary store may be a magnetic core matrix. The time scale is divided into cycles and each functional block is allotted one or more time-slots in the cycle. Binary adder.-Fig. 1 shows the arrangement when a functional block is allotted one time slot tn in each cycle, ACS denoting an access switch to the permanent store. At times tn in successive cycle likeordered binary digits of two binary numbers are applied to the gates IG, I<SP>1</SP>G of the function block, least significant digits first. Words read from PS will have a portion (I) comprising the sum digit which will be applied to the functional block as output, and a portion (A) comprising the carry digit which will be written in TS. If the numbers are 1101 and 1011, at time tn of the first cycle IG will gate 1 and I<SP>1</SP>G will gate 1, both to ACS. TS is empty and the first address is 110 at which in PS is stored 10. The 0 is output from the functional block and the 1 is entered into TS. The next address is 01 from the input gates and 1 from TS which leads to read out of the word 10. The next address is 101 again giving access to a data word 10, and the last addresses will be 111 reading from PS the word 11 and 001 reading from PS the word 01. In this way the sum 11000 is generated at the output of the functional block. Scale-of-ten counter.-Pulses arriving at random time-cycles but at time tn within a cycle are to be distributed over ten lines. At time tn input to the functional block is sampled, the a part of an address becoming 1 if a pulse is present, 0 otherwise. The b part is taken from TS which initially holds 0000. If no pulse arrives at tn the address is 0.0000 which results in 0000 being rewritten into TS and in a null output from the functional block. The first pulse to arrive results in an address 1.0000 which reads out from PS the word 0001.1000000000 of which the 0001 is sent to TS and the latter part as a parallel output from the block marks the first of the ten lines. The second pulse generates the address 1.0001 which reads out the word 0010.0100000000 from PS and so on through ten steps. The tenth pulse causes readout of the word 0000.0000000001 which restarts the cycle. More complicated operations require that more than one time-slot be allotted to the functional block and that the address of words in PS have more than two components. Fig. 4 shows apparatus for performing such operations and which includes a transfer store TRS, which is written into at one time-slot and read-out at the next. A scale-of- 1000 counter is allotted the time slots t n  to t n+2  and issues a pulse at t n+2  through gate OG after the reception of the 1000th pulse at gate 1G. Each PS word comprises three parts the additional part A<SP>10</SP> being 1 at every tenth pulse, 0 otherwise. A <SP>10</SP> is sent to TRS from where it is transmitted to ACS as part of the address of the next word of PS. The programme described above for the scale-often counter is used in each time slot with the difference that except on the 1000th pulse there is no output to the functional block (I = 0). At successive t n'@ ,IG is sampled and the scale-of-ten programme worked through. At the tenth pulse a one is entered in TRS. At the t n + 1's  before this, since gate IG is not open the address generated has been 00 (contents of TS) which has resulted in TS being regenerated. At the t n+1  1 after reception of the tenth pulse the address is 01 (contents of TS) and this results in the selection of a PS word with a portion A10 to enter into TRS for readout at tn+2. This portion is zero except at the tenth pulse (100, 200, &c.) when it is one. Thus at t n , the scale-of-ten programme is gone through to signal every tenth pulse, at t n+2  2 the programme is also gone through to signal every 100th pulse, and at t n+2  every 1000th pulse is marked by selecting a PS word having an I portion of 1 which is gated through OG. Dial pulse receiver and counter,-This programme using the apparatus of Fig. 4 uses four time slots t n  to t n+  3. In t n  t n+  1 from a basic clock frequency of 10 kc/sec.are derived line sampling pulses at 10 ms. intervals by using the decade counter programme twice to get a scale-of-100 counter. The sampling pulses issue from TRS at t n+2 . The state of the line at the previous sampling is known and this together with the result of the present sampling gives two digits of the PS address, the remainder of the address coming from TS. When the line is first looped the address is 01(TS). If the line is looped on the next examination the address is 00(TS). An open line after sampling a looped line gives 10(TS) but it is only on detection of an open line after sampling an open line, address 11(TS), that a new word for TS is read from PS. In this way spurious breaks are ignored. The new word steps a dial pulse counter. In t n+3 , the interdigital pause is detected. Using the 10 millisec. sampling signal generated at t n+2 , the line is sampled and the number of consecutive looped lines is counted when the count reaches 12 it is assumed that the interdigital pause has arrived and the dial pulse counter is reset. Telegraph signal regenerator.-On the detection of the start element of a received character, the line is sampled, assuming signal rate is 50 bands, at 10, 30, 50 ... 130 ms. thereafter. At 10 ms. if the line is at mark no signal is retransmitted and the start signal is assumed false. If the line is at space, a short space is initiated at the output. At other sampling times the output is caused to follow the input save at 130 ms. when a mark is initiated whatever the line condition. Times t n , t n+1  are used to generate 10 ms. interval sampling pulses as expalined above and on detection of two successive spaces only the alternate samplings are effective.