The 4-STAR is a Radio over IP (RoIP) device connecting up to 4 analog radios via an IP (SIP) network. E&M signaling on each port supports Push-to-talk (PTT) keying and includes a standard 4-wire full-duplex audio interface. Each port also includes an RS232/422 serial port and discrete input/output for enhanced radio control (e.g. frequency, mode, squelch, power) as supported by the MVP software. The 4-STAR can be directly connected to an MVP or used stand-alone.