Public switched telephone network calling method of frequency common communication system

摘要

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Public Switched Telephone Network (PSTN) communication method of a Trunked Radio System, and more particularly, to a public switched telephone network (PSTN) The present invention relates to a PSTN communication method of a frequency sharing communication system capable of automatically requesting a call connection by changing to a PSTN group number by pressing a call button without having to change to a PSTN group number.;In the public switched telephone network communication method of the present invention, each terminal reads all group numbers of the terminal in initialization from the EEPROM, stores the group numbers in the RAM, and then scans the operation status of the operation buttons of the terminal, The method comprising the steps of: checking whether the terminal has a group number capable of PS-capable communication when the call button is operated in the determining step; Changing a group number to a corresponding system and group and transmitting a PSIN paging signal to a repeater; receiving a recognition signal for the PSTN from the repeater; receiving a recognition echo for the PSTN;