The relay mode of dual-mode walkie-talkie can realize cross-network interconnection and emergency intercommunication, which is the key mode to realize "public-private integration. After the relay mode is turned on, the walkie-talkie can be used as a "bridge" to forward the received private network voice to the public network packet, or to forward the public network voice to the private network channel. This function effectively realizes the interconnection between public network and analog network, and has high practical value in emergency communication and complex networking scenarios. The intercom platform of public network intercom and the platform of dual-mode intercom must be consistent, and the standard of private network must be consistent, so that they can communicate with each other.