After discussing the trunking scheme of PABX,the paper intro- duces the design and implementation of Digital Trunk Module-DTM. The DTM is based on MH89780 (CETP Digital Trunk Interface Hybrid) and MT8980 (Digi- tal Time/space Crosspoint Switch) LSI chips.

• 本文史介绍一种程控用户交换机数字中继模块的实现方法。 它以加拿大 MITEL 公司的MH89780数字中继接口芯片(CEPT Digital Trunk Interface Hybrid)和 MT8980(8×32)时隙交换矩阵芯片(Digital Time/Space Crosspoint Switch)为基础来实现数字中继接口功能。