| 摘要 |
PURPOSE:To make easy the switching operation, by providing the clock generator supplying transmission clock and reception clock at loop test with a line switcher itself. CONSTITUTION:At loop test, a loop test controlling circuit 11 forms a test loop from a communication processor CCU of dual constitution at a loop test switching circuit 12 with the loop test indicating signal. In this case, the loop test from CCU can be made without using the transmission clock at CCU side, by supplying the clock for the transmission/reception data, transmission clock of a control circuit and reception clock from a clock generating circuit 20. |
