GB271155A - Improvements in or relating to telegraph systems - Google Patents

Abstract

271,155. Automatic Telephone Manufacturing Co., Ltd., and Harrison, H. H. Feb. 18, 1926. Restoring or modifying imperfect signals; repeating systems using contact-making relays; automatic telegraphs.-In a relay system for restoring imperfect signals in triplex telegraphy, the input line relay charges a condenser on receipt of a signal, and the output relay is operated by subsequent discharge of the condenser, the charging period being longer than the discharging period. In the apparatus shown the successive elements of a message are dealt with alternately by the groups a and b of contacts. The input relay LR makes contact at 1 or 2 according as a positive or negative signal is being received, and thereby applies a positive or negative charge, as the case may be, to the condenser K, if the distributor brush CBA, is wiping one of the contacts a, or to the condenser K2 if the brush is wiping a contact b. The brushes CBA1, CBA2, CBA3 are on a common shaft and the brush CBA2 lies on a blank segment a" when the condenser K, is being charged through a contact a, but when the brush CBA2 passes over a contact a' the condenser K1 discharges through the instrument R1, which may register or retransmit the signal. During the discharge of condenser K1 condenser K2 is acquiring a charge through a contact b, the brush CBA3 lying then on a blank contact b<11>, but when that brush reaches a contact b<1> (while the brush CBA2 at the same time reaches a blank contact a") the condenser K2 discharges through a recorder or repeater R2. Thus one signal element is dealt with by the parts a, K1, R1, and the next element of the same signal by the parts b, K2, R2, an a signal being recorded or retransmitted while a b signal is being received, and vice versa. The charge given to each condenser is large enough to ensure that the instruments R1, R2 be energized during the whole period of contact of the brush CBA2 or CBA3 with its contact a' or b<1>. Owing to the large initial value of the discharge current the conditions are favourable for rapid signalling.