Patent GB-850341-A (GB)
Title: Improvements relating to digit translating apparatus
Inventor: WARMAN BLOOMFIELD JAMES
IPC: H04Q3/42
Filed: 1955-12-30
Abstract: 850,341. Automatic exchange systems. SIEMENS EDISON SWAN Ltd. Dec.31, 1956 Dec. 30, 1955], No. 37403/55. Class 40 (4). In a translator for three digit codes, two digits enable one of a 10 X 10 array of gates to provide an output which enables 10 cold cathode route tubes in a 10 X 100 array of such tubes, and the third digit provides a disabling potential to all tubes except the particular 100 associated with the third digit, whereby only the particular route tube associated with the three-digit code is struck. As shown, Fig. 1, the registers apply D.C. potentials, whose durations represent digits, to code receiving units CRU1 ... 5, the units CRUI . . 3 receiving the three exchange code digits, CRU4 receiving the first numerical digit, and CRU5 receiving a signal indicative of the translated digit required. (The register demands the translated digits one at a time and releases the translator immediately it receives the required digit. In the first instance the translator sends two digits to the register, one indicating the number of digits in the translator, and the other indicating the value of the first translated digit). The translator TF comprises 1000 (or less) route tubes (one for each exchange code) divided into 10 groups of 100, the operation of nine of these groups being inhibited in accordance with the digit received by CRU3. The digits received by CRU1, CRU2 after a slight delay operate an array of 100 gates G1 to G100 the output of one of these operating the appropriate route tube in the uninhibited group. The route tubes are cross-connected to appropriate terminals on successive translation sending units TSU1 . . - TSUn, which are enabled successively (except the first two which are enabled simultaneously for reasons described above) in accordance with the digits received from the register by CRU5. The appropriate translation sending unit then sends a D.C. signal whose duration indicates the translated digit as determined by the cross-connection. If certain first numerical digits are barred for certain exchange codes, the register is arranged to hold up, at some stage, the demand for a translated digit until the first numerical digit is received. This is then transmitted to CRU4 together with the transmission of the exchange code to CRU1... CRU3. Firing of a route tube, and the reception of a barred digit for that route causes the circuit BDF to signal to the register that NU tone is to be reverted. Detailed description.-In a code receiving unit, Fig. 2, a counting tube MT1 is initially set by a PB10 pulse, Fig. 7, and reception of D.C. from the register on lead AT causes tube V 1  to pass P-pulses, Fig. 7, to tube V 2 , whose output steps the glow discharge in the counting tube to a position determined by the duration of the D.C. signal. According to the position of the glow one of tubes TC1 ... TC10 has its trigger primed for firing by the next anode pulse PB10. The actual instant of firing is however controlled by a pulse on lead Pc superimposed on the priming potential of the trigger. In the case of code units CRU3 - . . CRU5 terminals a, c (Fig. 2A) are strapped and the trailing edge of a PA11 pulse fires tube V 3 , the pulse for Pc being developed across resistor R44. In the case of units CRU1, CRU2 where a delay is required terminals b and c are strapped and terminal d strapped to terminal e. Thus a pulse received over terminal d at the instant of the trailing edge of PA11 is effective to strike V 3  only after a delay equal to the charging time of condenser C16. The firing of one of tubes TC1 ... TC10 raises the potential of a corresponding cathode lead. The (slightly delayed) outputs from CRU 1, CRU2 are applied to a 10 x 10 matrix of rectifier gates, Fig. 3 (not shown), to energize one of leads 1... 100, Fig. 4, each lead priming a row of ten route tubes in a 10 X 100 matrix of such tubes RT1 ... RT1000. Meanwhile however an undelayed output from CRU3 applied over one of leads LC causes all of tubes HHT1 ... HHT10 except one to fire, thereby inhibiting all tubes in the corresponding columns from firing. Thus only the appropriate route tube fires and its rise in cathode potential is communicated by diodes to one terminal in each of fields TT1, TT2 ... in accordance with the translation to be effected. Thus the TT1 terminal might indicate the number of digits in the translation, the TT2 terminal might indicate the fee and terminals in subsequent fields might indicate the counting digits. Each of the fields TT1 ... TTn is connected to field TT of its associated translation sending unit, Fig. 5. A translation sending unit is enabled by the receipt of the appropriate digit by unit CRU5, the output from the corresponding one of tubes TC1 ... TC10, Fig. 2, enabling tube V7, Fig. 5A, to be struck by a PA10 pulse, whereupon tube V6 is enabled to pass P-pulses for the stepping of the counter MT2 (originally zeroized by a PB10 pulse). Marking of a TT terminal prepares a corresponding one of tubes S1 . . . S10 and when the glow reaches the corresponding cathode this tube strikes to produce an output on lead h to the register. This output lasts until the end of the PA10 pulse and its duration is thus indicative of the value of the translated digit. For an exchange code in which some first numerical digits are barred, the outputs from the corresponding route tube is connected to one (say T1) of terminals T1 . . . T15. The corresponding one of terminals DD1 ... DD15 (say DD1) is connected to those of terminals N1 ... N10 corresponding to barred first digits. These terminals are energized from the code receiving unit CRU4 and the potential applied therefrom to the trigger of tube DI1 during the PB10 pulse, is maintained into the period of the subsequent PA10 pulse due to the action of the condenser resistance combination C71, R531. Tube DI1 thus fires and applies a pulse to the trigger of tube DS1 which is already enabled by potential over T1. Tube DS1 thus fires to pass a signal over lead k to the register, so initiating the release thereof and the reversion of NU tone. In the event of a spare code being dialled the corresponding route tube being unprovided none of the route tubes in the uninhibited column, Fig. 4, fires during the PAll pulse, so that the corresponding one of tubes ST1 ... ST10 is enabled to fire at the beginning of the next PA10 pulse, the resulting potential being applied over lead SP and terminal l, Fig. 6, to fire tube DU thereby signalling to the register, over lead k, that NU tone is to be reverted.