GB478447A - Improvements in or relating to communication systems - Google Patents

Abstract

478,447. Type-printing telegraphy. STEVENS, A. H. (International Business Machines Corporation) Sept. 12, 1936, No. 24935. [Class 40 (iii)] In a system using transmitting and receiving distributers and in which each character is represented by a single impulse, the impulses are differentiated with respect to time and also polarity so that the number of segments on the distributers is halved. The transmitting distributer 50 makes at each contact and over normally closed contacts 32a controlled by a pair of keys such as A, N, charging circuits for the corresponding pair of condensers 38 connected to opposite poles of battery 40. Operation of a key shortcircuits the corresponding condenser either directly as shown or by means of key-controlled lever and cam mechanism such as that described in Specification 438,464, [Group XVI], so that when the distributer next makes contact the condenser is charged positively or negatively depending on its connection to the battery. The charging impulse is transmitted over transformer 46 and a line or wireless channel to the receiver comprising a pair of normally quiescent valves 62, 63 operated respectively by negative and positive impulses. Condenser discharges or battery directly controlled by the keys may alternatively be used for impulse transmission. The outputs of the valves are connected over amplifiers to printing magnets 18 in two sets connected in pairs to contacts of the receiving distributer 51 which is maintained in synchronism with the transmitting distributer in the manner described in Specification 442,596, a negative synchronizing impulse being transmitted over contact 20. The type-levers may be operated as described in Specification 438,464.