Title: Line circuit for telecommunications exchange using TDM

Abstract: Disclosed is a line circuit providing the normal line circuit functions and key system control functions within an exchange using time division switching. The line circuit may be used interchangeably for key telephones or non-key telephones. In the former case, the circuit provides the well-known key telephone features for multiple line access at each station of a plurality of stations. Each line circuit provides electronic signalling controls, such as lamp flash indicating a call awaiting an answer, lamp wink indicating a line is on a hold condition, and the fully lit line busy indication, together with audible controls for a called line, and also provides an inverted flash signal at the line circuit for trouble or problem situations.

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Inventors: Korsky, Viacheslav (Guelph, CA, US)
Elmer, Christopher (Guelph, CA, US)

Application Number: 516163
Filing Date: 1974-10-21
Publication_date: 1976-12-14
Assignee: International Telephone and Telegraph Corporation (New York, NY)
Primary Class(es): 370/271 370/375, 370/384
Other Classes:
US Patent Ref:

3244815	May, 1966	Anderson et al.	179/99.
3385935	May, 1968	Anderson et al.	179/99.
3420961	Jan, 1969	Averil, Jr.	179/18.
3453396	Jul, 1969	Lacey et al.	179/99.
3715516	Feb, 1973	Ebrahimi	179/18.
3787631	Jan, 1974	Lewis	179/99.
3789152	Jan, 1974	Medill et al.	179/15.
3914559	Oct, 1975	Knollman	179/99.

Other Refs:
Primary Examiner: Claffy, Kathleen
Assistant Examiner: Myers, Randall P.
Attorney: Raden; J. B., Chaban; M. M.