... 2G/2.5G/3G/3.5G network and frequency modulation (FM) network.It adopts high-powered industrial 32-bits CPU and embedded real ... , SMS to voice warning, GPRS data to voice warming, FM network warning, local interphone wireless warning, local microphone warning, pre-set ... say, the server station transfers warning messages to the client station by FM network. Each of these three type devices can achieve ...