internal exchange是什么意思

用法例句

The main function of the system is presented, as overcoming the simple dispatcher function of power line carrier exchange system and realizing DP/DTMF operation mode, internal exchange and relay communication modes.

较详细地叙述了ＷＣＺ－ ２ 型微机自动交换系统的设计思想，阐述了该系统实现的主要功能，突破了电力线载波机中交换系统的单一调度功能，实现了ＤＰ／ＤＴＭＦ信令工作方式、内部交换以及各种中继通信方式。