Telephonic communications – Substation or terminal circuitry – Amplifying
Patent
1986-11-14
1988-05-31
Ng, Jin F.
Telephonic communications
Substation or terminal circuitry
Amplifying
379387, H04M 160
Patent
active
047486643
ABSTRACT:
To provide an adequate dc supply to the electronics of a telephone, when on hook or off hook, there is a transistor (T2) with its emitter-collector path in one line wire, and a storage capacitor (Cpsu) across the input to the telephones's circuits. This capacitor is charged up and maintains dc supply when the line voltage (at A) falls below a preset level. The base of this transistor is connected via another transistor (T1) to the other line wire. The speech output (V.sub.IN) is connected via an operational amplifier (A) to the base of the second transistor (T2). Hence the dc supply and the speech output are in parallel.
REFERENCES:
patent: 4233474 (1980-11-01), Hishinuma et al.
patent: 4680789 (1987-07-01), Sijbers et al.
Ng Jin F.
STC PLC
Vaas R.
LandOfFree
Telephone power supply 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 power supply, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Telephone power supply will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1879405