Orderwire communication system

摘要

An orderwire scheme for a multichannel repeated communication network contains an auxiliary communication link that is coupled to communication sites along the network and is configured of a pair of orderwire links each formed of a conventional interstitial copper wire pair. To carry out supervisory functions with respect to each of the stations along the communication link, messages are conveyed from a control facility coupled to or as part of the network to respective stations along the link in the form of command instructions. These messages may contain a request for information from the addressed site as to equipment conditions at the site or a directive that the equipment at the site perform a particular task. In reply to the command message sent to it the addressed site returns a response message back to the control facility representative of the action taken including any data requested by the instructions. In addition to providing a distributed communication link over which supervisory command and response messages can be transmitted among the stations along the orderwire link, a further facility for conveying voice communications over the same orderwire link is provided. In order to implement the exchange of command and response messages among the various sites of the network, supervisory signals are transmitted using digitally encoded ON/OFF keying of frequency tone signals.