Abstract: In view of problem that communication systems of non-central-switch calling are unable to communicate with each other, the paper put forward a scheme of realizing communication between non-central-switch calling systems, introduced composing, working principle and hardware and software design of non-central-switch calling communication systems, mainly expounded design method of hardware circuit of merger separator.The actual operation showed that the designed communication system can realize communication and management between non-central-switch calling communication systems, and haveadvantages such as high reliability and stable performance.