Telephone charging signalling detector suitable for central offi

Details Telephone charging signalling detector suitable for central offi Telephone charging signalling detector suitable for central offi

1990-06-19

1993-06-22

Dwyer, James L.

Telephonic communications

Substation or terminal circuitry

Conversion of signal form

379399, 379236, 379235, 379231, H04M 174

Patent

active

052221296

ABSTRACT:
Detector for telephone charging signalling in the form of periodic pulses derived from alternating current signals at specific frequencies transmitted in analog form by means of a line (2) comprising two wires (A, B), for example to a central office line interface circuit of a private telephone installation connected to an analog network subscriber line. The detector comprises an input filter (4) centered on the frequency (Ft) of the expected signalling, a sample and hold circuit (6) connected to the output of the input filter (4) and to the output of a clock (7) supplying a signal (HE) whose frequency (FE) is close to the value (Ft), a lowpass filter (8) within the band of which the characteristic signal from the sample and hold circuit is included, and a level detector (9) adapted to supply a presence signal for a characteristic signal at a level above a predetermined threshold at the output of the lowpass filter (8).

REFERENCES:
patent: 3393274 (1968-07-01), Ingraham
patent: 3506789 (1970-04-01), Brockschmidt et al.
patent: 4001515 (1977-01-01), Zorzy
patent: 4053709 (1977-10-01), Velu et al.
patent: 4270027 (1981-05-01), Agrawal et al.
patent: 4479188 (1984-10-01), de Keijzer
patent: 4563547 (1986-01-01), Booth
patent: 4856059 (1989-08-01), Halbig
patent: 4914690 (1990-04-01), Hagedorn
patent: 4930153 (1990-05-01), Hagedorn

Affiliated with

Also associated with

Rating

Telephone charging signalling detector suitable for central offi does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Telephone charging signalling detector suitable for central offi, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Telephone charging signalling detector suitable for central offi will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1445500