| 摘要 |
PURPOSE:To make it possible to shorten the time required for trunk selection and reduce deviation of the trunk selection time dependent upon trunks, by discriminating the idle state and the busy state for respective trunks of a trunk group indicated as idle. CONSTITUTION:Before discrimination of states of memories M0-M5, a high-level scanning pulse is generated from scanning circuit S. Meanwhile, since signals indicating the busy state are output to idle and busy indicating leads B0, B1 and B2, they are all high-level. The output terminal of NAND gate G0 becomes low-level during the scanning time dependent upon scanning circuit S. The output signal of gate G0 is held in register R0 by clock pulse (C). Since leads B3, B4 and B5 are low-level in idle indication, the output terminal of gate G1 is high-level. For example, states of registers R0 and R1 are discriminated, and the busy state of memory M3 is discriminated, and the idle state of memory M4 is discriminated, thereby selecting trunk TRK4. |
