| 摘要 |
The subrate control channel exchange system uses a part of bits in a control channel time slot, for example, an 8-bit time slot in transmitting communications control data, and uses the rest of the bits in transmitting communications data such as voice, etc. For example, even if the transmission speed of a transmission line is 64 kb/s, the present invention aims at improving the utilization of the line when a speed of approximately 16 kb/s is applicable. In an ISDN network, which establishes communications by multiplexing communications data applied from a source terminal unit to a destination terminal unit over an exchange network together with communications control data, the present invention comprises a subrate exchange trunk for multiplexing in a single time slot only significant bits in low speed data applied from a plurality of low speed terminals connected to the exchange network, and a bit unit exchange switching unit for multiplexing in a control channel time slot an output of the subrate exchange trunk together with control data of fewer than 8 bits. |
