Interoperability Gateway

The Interoperability Gateway is a multi-channel analog voice interface for OpenSky®, NetworkFirst®, and Project 25 (Phase 1 and Phase 2) packet-switched digital networks. The modular design supports up to twelve audio channels and is used to connect existing analog equipment, such as consoles and analog voice base stations, to the Internet Protocol (IP) digital network.

Dispatch Console Interface

Each Interoperability Gateway receives and transmits packetized digital voice over an Ethernet interface for connection through a switch to the Voice, Interoperability, Data, and Access (VIDA®) network. Interoperability Gateway modules offer a 4-wire balanced line level interface for the audio connection. Audio amplitude may be adjusted under software control, and signaling lines are opto-isolated and may be operated in “open collector” mode.


When used to provide interoperability with other communications systems, network users are automatically connected to legacy system users by selecting them as designated voice groups. This provides capabilities for crossband inter-system operation. Additionally, the Interoperability Gateway supports the MDC-1200 signaling format for User ID and Emergency functions.

Digital Voice Coding

Digitized voice within the digital network is coded using Advanced Multiband Excitation (AMBE®) for OpenSky systems or Improved Multiband Excitation (IMBE) for P25 systems. AMBE/IMBE digital voice is then encapsulated into IP packets and sent along with control messages into the IP digital network. Additionally, the Interoperability Gateway supports the use of Adaptive Differential Pulse-Code Modulation (ADPCM) for NetworkFirst systems and transmission of analog inputs to other VIDA products which support ADPCM, such as the C3 MaestroIP™ and VIP Consoles.