| 摘要 |
A SWITCHING ARRANGEMENT THAT CAN BE CONNECTED IN A COMMUNICATIONS CHANNEL THAT COMPRISES A PAIR OF LINES BETWEEN SETS OF TERMINAL EQUIPMENT, WHICH COMPRISES: (I) A SERIES SWITCH FOR CONNECTION IN EACH OF THE LINES; (II) A SHUNT SWITCH FOR CONNECTION BETWEEN THE LINES; AND (III) A CONTROL CIRCUIT THAT CAN ACTUATE THE SERIES SWITCHES AND CAN ACTUATE THE SHUNT SWITCH ON RECEIPT OF A SIGNAL SENT ALONG THE CHANNEL; WHEREIN THE CONTROL CIRCUIT CAN ACTUATE THE SHUNT SWITCH AND THE SERIES SWITCHES ON RECEIPT OF ONE OR MORE SIGNALS BUT THE SHUNT SWITCH WILL REMAIN CLOSED OVER A DIFFERENT TIME PERIOD THAN THAT DURING WHICH THE SERIES SWITCHES REMAIN OPEN, IN ORDER TO ALLOW DIFFERENT TESTS TO BE PERFORMED ON THE CHANNEL, AND WHEREIN ONE OR MORE OF THE SWITCHES COMPRISES A SOLID STATE SWITCH.(FIG 1)
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