This paper introduces how to implement the functions of the select calls,group calls and complete calls by using the second-developed control and interface protocol of the GP88s handset,and how to write personal number or grouping number into handset by key-press programmable method.

This paper presents a new keyboard-coding circuit,which is realized by conversely applying multi-Switch,swiftly scanning multiple-switch address bus using incremental binary code, changing locked address by its inner electronic switch,and discusses the principle of this kind of keyboard-coding circuit.