| 摘要 |
PURPOSE:To avoid concentration of a base band signal line and a control signal line by connecting sequentially plural data switching circuits with less selection number in cascade and allowing a response signal of each data switching circuit to control the circuits sequentially. CONSTITUTION:One set of the 1st signal line group comprising three sets of input signal lines A1-C1 is selected by the control signal of the data switching circuits 15-1-15-3, connected to a base band output signal line D1 as functioning the 2nd signal line group and connected to a modulator of a spare radio line. Further, output signal lines of the circuits 15-2, 15-3 are connected sequentially to input signal lines C1, C2 of the circuits 15-1, 15-2. Then the circuits 15-2, 15-3 select any of inputs A, B, C and when any of active radio lines REG1-5 is switched to a spare radio line SP and response signals 108-2, 108-3 representing the selective connection are transmitted as the control signal. |
