Improvements in or relating to register-senders for use in telephone systems

753,002. Automatic exchange systems. AUTOMATIC TELEPHONE & ELECTRIC CO., Ltd. Nov. 6, 1954, No. 32179/54. Class 40 (4). A pre-transmission pulse is applied to the counting circuit of a register-sender and the corresponding impulse to line is suppressed, the pre-transmission pulse testing whether or not a digit has been injected into the counting circuit. If so, impulses are sent to line until the counting circuit is restored to zero and a further impulse is sent to compensate for the pre-transmission pulse. A common translator serves several registers. The counting circuit and impulse sender are shown in Fig. 1, the associated control circuit in Figs. 2 and 3. The storage circuits are not shown but are each associated with a display element DE comprising four tubes arranged on the binary principle, the display elements being effective sequentially to inject the corresponding digit into the left-hand side of the counting circuit. When the register is taken into use relay B (not shown) operates to connect H.T. to lead SHT and a start pulse is applied to lead ST. Tubes RA, RB, ZA, ZB, RJA, RLA, BCB, BEB, BGB, BJB strike and relay SZ energizes to short-circuit the loop impulsing springs, Fig. 1. When the translator has determined the routing digits application of a display pulse to lead DP causes the first routing digit to be entered in binary form on tubes WD, XD, YD, ZD. All the tubes of each stage of the counter, say WD, BD, BCA, BCB, have a common anode resistor so that when a tube of one pair, say WB, BD, is struck the conducting tube of the other pair BCA, BCB is extinguished. According to whether one of the left-hand or right-hand pair is conducting so the particular stage of the counter is said to be in left-hand or right-hand condition. Each stage also includes a pulse-repeating tube such as PRD primed from the right-hand pair of tubes. When PRD fires it repeats the pulse to BD and also to the next stage. Counting out routing digit. Relay D operates to a loop on the outgoing route and energizes relay IG at the next opening of springs MAG which now control relay IMP. Each operation of IMP extinguishes tubes ZA, ZB, RA and strikes OG to pulse the first stage of the counter circuit. Impulses are meanwhile sent to line by the loop springs in anti-phase to the springs MAG, the first opening of the loop springs being ineffective because tube RJA is conducting at that time so that relay SZ is energized. If the first stage of the counter is in right-hand posi