In this paper, we present a Linux-based Radio over IP system. The system is a cost-effective IP interoperability communication system that integrated the mobile radio, typical public switched telephone network lines, cell phone, native IP devices etc. All equipment can access the communication with each other via IP network using hardware-software coordination on asterisk SIP IP-PBX running under Linux OS. After the evaluation of performance tests, we can determine the basic configurations for the system in order to readily for use as an interoperability system to support an emergency situation communication.