Switching system for telephone installation - having all receiving and transmitting switching units connected by single wire

摘要

The telephone system has the number of lines reduced by grouping together signalling and switching wires for a given process into a single wire connecting all parallel terminals including the central unit. All switching units (receiving and transmitting) are connected to only one single wire. This wire is supplied with a dc potential and a keyed potential to denote outgoing transmission and outgoing receive signals. Thus, the signals on the signalling and switching wires are distinguished, with the signalling and switching wires connecting the parallel terminals.