04076961 is referenced by 28 patents and cites 4 patents.

An automatic switching unit for connection to a modem at a remote site in a data communications network. The switching unit normally connects the modem to a primary data transmission path. If the primary path malfunctions, a central site operator can telephone the remote site and establish a secondary data transmission path. The switching unit answers the incoming calls and automatically disconnects the modem from the primary data transmission path. Once the primary data transmission path has been repaired, the central site operator causes the switching unit to return communications to the primary data transmission path. In one embodiment, this transfer can be made while maintaining communications over the secondary data transmission path.

Title
Automatic switching unit for data communications network
Application Number
508278
Publication Number
4076961
Application Date
March 9, 1976
Publication Date
February 28, 1978
Inventor
David E Williams
Andover
MA, US
Jerry L Holsinger
Boston
MA, US
Agent
Cesari and McKenna
Assignee
Intertel
MA, US
IPC
H04B 3/00
H04M 11/00
H04M 9/00
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