Telephone line tester

Details Telephone line tester Telephone line tester

1986-08-08

1988-04-05

Schreyer, Stafford D.

Telephonic communications

Diagnostic testing, malfunction indication, or electrical...

Testing of network terminating interface, subscriber trunk...

H04M 124

Patent

active

047364033

ABSTRACT:
A circuit tests the telephone line for polarity, line voltage and open/short circuit. The polarity test is accomplished using opposite polarity LED elements which generate a visual indication of correct or erroneous polarity. The line voltage is tested by comparators which compare the line voltage to predetermined limits and generate a visual indication if the voltage is within or without the limits. The tip or ring ground short circuit is detected by monitoring the AC voltage while in the ON HOOK state. If a ground short is present on either tip or ring of the telephone line, the AC voltage becomes high due to power frequency coupling. A comparator detects this voltage and generates a visual indication if the voltage is greater than a predetermined value.

REFERENCES:
patent: 3916381 (1975-10-01), Johnson, III et al.
patent: 4074187 (1978-02-01), Miller et al.
patent: 4197435 (1980-04-01), Jackson et al.
patent: 4317967 (1982-03-01), De Vries et al.
patent: 4385336 (1983-05-01), Takeshita et al.
patent: 4513179 (1985-04-01), Phillips et al.
patent: 4575588 (1986-03-01), Vande Uyver
patent: 4588862 (1986-05-01), Grabowy
patent: 4600810 (1986-07-01), Feldman et al.

Affiliated with

Also associated with

Rating

Telephone line tester 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 line tester, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Telephone line tester will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2238893