| 摘要 |
PURPOSE:To contain 2B+D(1.4Kb/p+64Kb/p+16kb/p)-pieces of digital subscriber's lines by providing a means to identify a line exchange call from a packet exchange call at every subscriber's line, a means to execute the rate conversion at every call, a means to decompose a packet data and output it as a serial data, and a means to cut-off/connect a packet through D-channel. CONSTITUTION:Whether the data B1RCV of B1-channel is a line exchange call or a packet exchange call is informed to a microprocessor muP through an interface circuit LAPD for D-channel by means of a signal data through the D-channel. The muP, under a prescribed program sequence, instructs, an input/output control circuit IO to convert the rate in case of a line exchange call. But if in case of a call requesting for a packet exchange service, an input data is inputted to the muP via a serial interface circuit SRI 1. The P accumulates this input data in accordance with a prescribed program, and transmits it to a packet assembly circuit X25 1. As a result, a digital exchange abundant in flexibility and capable of varied services can be constituted.
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