发明名称 |
TELECOMMUNICATION SYSTEM LOOP-BACK UNIT |
摘要 |
A loop-back unit for connection at the subscriber's end of a line (15) to provide a loop-back line testing facility, the unit comprising a transformer (1) with a first winding (3) and second winding (5) of relatively high inductance, connected in series across the line, and a third winding (7). In normal operation the subscriber's unit (17) is connected across the second winding and the transformer is transparent to signals on the line. To test the line a tone is applied to the line which is detected by a detector (25) connected across the third winding and in response to the detector output a control circuit (23) operates a switching arrangement (21) to disconnect the subscriber's equipment temporarily from the second winding and apply a test tone across the second winding. The unit is capable of satisfactory operation despite faults in the subscriber's equipment. |
申请公布号 |
DE3375269(D1) |
申请公布日期 |
1988.02.11 |
申请号 |
DE19833375269 |
申请日期 |
1983.03.30 |
申请人 |
THE GENERAL ELECTRIC COMPANY, P.L.C. |
发明人 |
HOMER, JOSEPH ALBERT |
分类号 |
H04M3/30;(IPC1-7):H04M3/30 |
主分类号 |
H04M3/30 |
代理机构 |
|
代理人 |
|
主权项 |
|
地址 |
|