1975-08-01
1976-08-24
Stewart, David L.
1791753R, H04M 124
Patent
active
039768490
ABSTRACT:
A test unit for testing the wiring connections in modular telephone installations. The unit consists of a housing with an input jack to receive the standard plug used to connect the telephone wiring to a handset. The jack has four terminals, one pair corresponding to the green and red(tip-ring) line wires, and the other pair corresponding to the yellow and black (ground and lamp a.c.) line wires. The tip-ring terminals are connected in the housing through a first diode, a Zener diode and a resistor to a "tip-ring" L.E.D. The a.c. terminals are connected in the housing to a "lamp" L.E.D. through a diode and a transistor, controlled by a network including a blocking capacitor. When the telephone line plug is inserted in the test unit jack, the "tip-ring" L.E.D. will light only if the "tip-ring" line voltage is correct in magnitude and polarity, and the tip ring line conductors have not been interchanged with the a.c. line conductors. The "lamp" L.E.D. will light to indicate proper a.c. voltage on the a.c. line conductors. If the a.c. voltage is too low the "lamp" L.E.D. will be dim. The "lamp" L.E.D. will not light if the a.c. line conductors carry d.c. voltage.
REFERENCES:
patent: 2367013 (1945-01-01), Edmonds
patent: 3711661 (1973-01-01), Garrett
patent: 3870836 (1975-03-01), Kusama
patent: 3922507 (1975-11-01), White
Levy Sherman
Melco
Stewart David L.
LandOfFree
Telephone wiring 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 wiring tester, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Telephone wiring tester will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-780107