GB957404A - Improvements in or relating to teleprinter apparatus - Google Patents

Abstract

957,404. Telegraphy. SIEMENS & HALSKE A.G. March 29, 1963 [March 30, 1962], No. 12470/63. Heading H4P. In a telex system, when a station calls a subscriber the subscriber replies with its identity and automatically follows this with a preset message such as " subscriber absent until . . .". The Figure shows part of the subscriber circuitry, consisting of switching unit Fg, telex apparatus Tn, and the automatic call-answering transmitter LS. When a calling signal is received by unit Fg over the exchange line, energization of receiving relay ER causes h1, h2 to be closed and motor M and relay U to be energized. This results in the subscriber sending its identity to the calling station, during which period Ng is closed whereby capacitor C is charged. When the subscriber has stopped transmitting Ng opens and C, in discharging, energizes relays B, V which lock up. Relay V controls the transport of a loop of perforated (or magnetic) tape containing the preset message, preferably preceded by ringing symbols. The preset message is thus sent to the caller, and at the end of the message a particular character results in energization of relay A so that the transport relay V is de-energized. Since B is locked up, b is open so capacitor C can not re-charge when, at the end of message, the calling station and subscriber exchange identities. When the caller sends an end-ofmessage signal, h1, h2 open so that teleprinter motor M is stopped. If desired, instead of providing a contact Ng controlled by the answer-back unit the unit LS may include means for recognizing the WRU calling signal which causes automatic transmission of the preset message after a time delay of about 7 seconds.