PORTABLE TESTER FOR TELEPHONE SUBSCRIBER LINES

• US 3,870,836 A
• Filed: 01/31/1974
• Issued: 03/11/1975
• Est. Priority Date: 02/02/1973
• Status: Expired due to Term

• Current Assignee: Mikio Kusama
• Original Assignee: Mikio Kusama
• Inventors: Kusama, Mikio
• Primary Examiner(s): Cooper, William C.
• Assistant Examiner(s): Olms, Douglas W.
• Application Number:
  US05/438,423
• Time in Patent Office: 404 Days
• Field of Search: 179/175.3R,175.2D,175.1R,175
• US Class Current: 379/21
• CPC Class Codes: H04B 3/46 Monitoring; Testing
• CPC Class Codes: H04M 3/30 for subscriber's lines , for the local loop

Abstract

A portable tester for telephone subscriber lines equipped with line testing functions such as measurement of line insulation, line capacitance, loop or shortcircuit resistance, line voltages, and further having function for sending calling signal to a working subscriber either for an exclusive line subscriber or party line subscribers, supervising function for the answer of a called subscriber and communication facility with a working telephone subscriber telephone set or unworking telephone set or with a magneto-telephone set and also provided with a monitoring function in order not to disturbe a telephone in use.

Claims

1. A portable tester for telephone subscriber lines provided with subscriber line connecting terminals L1 and L2, further line connecting terminals L3 and L4, headset connecting terminals T and R and a ground wire connecting terminal G and further provided with a test circuit and a speech and ringing circuit, wherein the test circuit comprises;

a reverse key S5 for reversing said lines L1 and L2, a first test key for connecting the lines L1 and L2 to the test circuit or to the speech and ringing circuit, a second test key S3 for reversing said lines leading to a dc meter circuit, a dc meter circuit connected to said second test key S3 and including further switching key S4 for switching the meter circuit including a dc meter M in either of the following three circuits of the following, a series resistance circuit for measuring voltages between terminals of the meter circuit, a series high dc voltate circuit for measuring insulation resistance between the terminals, a series low voltage and low resistance circuit for measuring low resistance between the terminals, a further key S2 for connecting ground from the ground terminal G to either side of the meter circuit by Use of said second test key S3; and

the speech and ringing circuit comprises, an oscillator for producing about 16-25 Hz ac ringing voltage by an excitation of housed battery, a neon lamp shunt connected to an output circuit of the oscillator for supervising an answering condition of a called subscriber, a key S11 for selectively connecting the lines L1 and L2 or lines L3 and L4 to said speech and ringing circuit, a monitoring key S7 for inserting a monitoring condenser of small capacitance in series with the terminals T and R for connecting a headset in order to monitor the condition of line to be tested, a speech circuit to be fed by a local battery, key S9 and S10 for connecting said local battery to the line terminals, and a shunt resistor inserted in parallel with the output circuit of the ringing oscillator to prevent repeated excitation of relay groups provided in the exchange.

2. A portable tester for telephone subscriber lines as claimed in claim 1, further comprising a key S8 for sending the ringing signal between the ground terminal and one of the subscriber line terminals.