| 摘要 |
A conduction test syst. for an emergency telephone which was capable of checking each telephone (TEL1-TELn) from receiver (TC) and receive the calling signal during test, was manufd. Receiver (TC) connected with the testing line of telephone was composed of the cct. for inverting the polarity having a coupling s.w (SWo) (SWo') and relays (DS), a current meter (AM), and a conduction test cct. (TS) having a resister (R) for generating the volt. to the common line (CL).
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