In a data transmission system comprising, for example, a facsimile transmitter connected to a facsimile receiver through a public telephone network, failure or malfunction sensors are provided at the transmitter and receiver which generate failure signals having the same frequency as the telephone network...http://www.google.fr/patents/US4112467?utm_source=gb-gplus-shareBrevet US4112467 - Failure mode control apparatus for electronic graphic data transmission system
Failure mode control apparatus for electronic graphic data transmission system
