Analog telephone circuit for digital telephone system

Details Analog telephone circuit for digital telephone system Analog telephone circuit for digital telephone system

1984-06-01

1988-07-19

Brown, Thomas W.

Telephonic communications

Multi-line or key substation system with selective switching...

With exclusion or priority feature

379166, 379394, 379399, H04Q 500

Patent

active

047590599

ABSTRACT:
An interface circuit for interconnecting an analog telephone device with a digital telephone system includes an independent power supply (58) for driving the loop termination on an analog telephone device (22). An impedance matching circuit (54) and a summing network (42) are utilized to both couple the signal from the analog telephone device (22) to the analog input of a key service unit (10) and match the impedance therebetween. A switch, (46) is provided to disconnect the analog port of a digital telephone device (12) that is compatible with the key service unit (10). When the analog telephone device (22) is in the off-hook mode, a switch control (52) opens the switches (48) and (50) of switch (46). The digital telephone device (12) is under the control of a digital transmission line (20) to maintain an analog interconnection in the key service unit (10). The analog telephone device (22) operates on an independent loop termination with an independent loop current. The signal generated in the loop is summed with the analog port (18) of the key service unit (10) through the summing network (42). In this manner, an inexpensive analog telephone device (22) with a non-compatible termination requirement can be utilized on a digital telephone system such as a key service unit (10) or a PBX.

REFERENCES:
patent: 3914559 (1975-10-01), Knollman
patent: 4085449 (1978-04-01), Walsh et al.
patent: 4088844 (1978-05-01), Kinnaird, Jr.
patent: 4142075 (1979-02-01), Olschewski
patent: 4238644 (1980-12-01), Dijkmans et al.
patent: 4322581 (1982-03-01), Christain et al.
patent: 4456991 (1985-06-01), Chea, Jr. et al.
patent: 4514597 (1985-04-01), Kikuchi et al.
patent: 4521643 (1985-06-01), Dupuis et al.
patent: 4535199 (1985-08-01), Zink
patent: 4572928 (1986-02-01), Nishimura et al.
"The Switched Network Transaction Telephone System", Froehlich et al., The Bell System Technical Journal, vol. 57, No. 10, Dec. 1978, pp. 3475-86.
"Skinny-Wire Key Telephones and the Rolm CBX", J. Kasson, Conference: 1976 National Telecommunications Conference, Dallas, Tex, U.S.A. (29 Nov.-1 Dec. 1976), pp. 11.4-1-11.4-4.

Affiliated with

Also associated with

Rating

Analog telephone circuit for digital telephone system does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Analog telephone circuit for digital telephone system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Analog telephone circuit for digital telephone system will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-602100