GB1367214A - Teleprinters - Google Patents

Abstract

1367214 Digital transmission; teleprinters SIEMENS AG 20 Sept 1972 [4 Nov 1971] 43439/72 Heading H4P The direction in which a cylindrical typecarrier TT in a teleprinter should be rotated to reach most quickly its desired new position is determined by first simulating its rotation in a fast counter PZ. The angular position of the carrier TT is conveyed by a pulse disc TS to a first counter BZ which stores its initial position in the form of a five bit code. When a new required position is called for by a corresponding 5-bit code received at a shift register ER, gates G2 respond to a control unit ST and transfer the contents of BZ to the fast counter PZ. High frequency pulses (200 kHz) then step the counter PZ until either identity of the state of PZ with the received code at ER is detected by a comparator V, or else the number of h.f. pulses (counted at TZ) reaches half the number of type positions on the carrier TT (e.g. 16), whichever occurs first. If identity is reached first, the output of a trigger K remains unchanged, and a signal V 0 /R enables a gate SST to pass stepping pulses to a stepping motor SM to drive the carrier TT in a forward direction (corresponding to that simulated in PZ). If identity is not reached first, counter TZ causes trigger K to change state and this causes the stepping motor SM to be driven backwards. During the actual stepping of the carrier to its new position, the contents of counter BZ are compared directly in V with the received code at ER, and when identity is reached, stepping stops and a signal A initiates printing of the appropriate character.