Network Radio always has three elements:
1. Hardware
2. Service
3. Connection
Hardware - There is a growing availability of hardware, some good some bad, so do your homework before investing!
Service - Our Lynx7 service is an example of a commercial, enterprise grade push-to-talk service. Other examples of free to use services are Zello and Echolink, although to use some Echolink services you need to be a licensed Radio Amateur.
Connection - Most devices will allow you to use WiFi, but the service generally works better over direct cellular data connection (3G/4G) for which a SIM card and data plan are usually required.