GB237666A - Improvements in or relating to the recording of telegraphic signals transmitted over telephone lines - Google Patents

Abstract

237,666. Engelberg, A. May 12, 1924. Exchange systems and apparatus.-In a system in which telegraphic signals transmitted by a calling party are recorded at a wanted subscriber's station, a signal is given to the calling party if the recording apparatus at the distant station is operating properly. The transmitted message is normally recorded at the sending station as well as at the receiving station, but a switch may be provided to cut out the recorder at the sending end if desired. The apparatus 7 at each station comprises an electromagnet 9, Fig. 2, the energization of which causes a pin 14 to perforate, a tape 16, whilst at the same time an arm 12 rocks one arm 33 of a pivoted U-shaped lever, the other arm 32 of which permits a spring plate 27 to withdraw a pin 26 from a perforation in a gear wheel 29 and so set the clockwork 24 in operation to drive the tape 16. A switch 34 is closed by the spring 27 as long as the clockwork is running. Fig. 5 shows the circuit arrangements for two stations interconnected through an exchange 56. The operation of a sending key 47 at the transmitting end completes a circuit from battery 35, contacts 53, 50, local recorder 7, conductor 43, exchange 56, conductor 43', distant recorder 7' and contacts 52<1>, 49<1> to ground in which circuit both recorders operate. As soon as the clockwork of the apparatus at the receiving end is released, the closure of switch 34<1> completes a circuit 49<1>, 52<1>, 51<1>, 34<1>, 44<1>, 44, 48. 54. 53, 35 in which lamp 48 at the sending end lights to indicate the operation of the recorder at the distant station. The switches 49, 49<1>, are closed against the action of gravity as long as tape is passing over the guide 18, Fig. 2, hut are opened in the event of breakage or exhaustion of supply. The key 47 and lamp 48 may be mounted on a single base, associated with the remaining apparatus by a 5- wire cable 60.