| 摘要 |
PROBLEM TO BE SOLVED: To surely attain the service of direct speech among plural slave sets without increasing traffic of a radio speech channel and to allow a slave set to call other slave sets in the radio zone simultaneously with respect to the speech system among the plural slave sets. SOLUTION: Each of plural slave sets is provided with a control means 1 that selects itself to be in the main slave set mode or in the sub slave set mode and executes communication in the selected mode, an A/D converter means 2 that convert a transmission voice signal into voice data with plural coding speeds respectively, and a D/A converter means 3 that converts the received voice data with a corresponding to coding speed into a voice signal. The main slave set uses a call signal of a control channel to inform the operating condition of an incoming voice transmission slot and a coding speed of transmission data depending on number (n) of sub-slave sets to each sub-slave set, and each sub-slave set sends incoming voice data with the informed coding speed by an informed incoming voice transmission slot. |
