The Remote Interface Unit (RIU) is a small, DSP-based, networked device providing remote audio and digital I/O sampling and conversion for multiple operators in communications networks.

Used in conjunction with ASTi's DACS processing equipment and Time Division Multiplex (TDM) technology, the RIU is used to create an easily scalable network of stand-alone communication nodes. This flexible architecture addresses both audio and I/O distribution problems encountered in large, multi-user applications.

In a typical configuration, operator headsets, speakers, communication panels, and other equipment are all connected to the RIU. Multiple RIUs are connected along standard network cable to form a high-speed TDM ring. Digital audio and control information are passed back and forth between each RIU and a centrally located DACS processing node.

A DSP-based TDM master, resident in the DACS, provides TDM network control and real-time mixing of any combination of RIU audio channels, as well as synthesized or recorded sounds. Radio effects such as noise injection, fade, frequency matching, squelch, and occulting are also handled. Signals are switched and routed based on both a user-defined model resident in the DACS processing node, and control data from simulated communications panels or Hand-Held Terminals connected directly to the RIUs.

Depending on the application, up to 14 RIUs or 24 voice channels can be supported by a single TDM ring. Up to three TDM rings are supported in a single, central DACS processing node. DACS units can also be networked, providing a highly scalable architecture suitable for applications with just a few operators to applications involving a large number of remote operators.

Typical TDM configuration with RIUs:

See the links in the right-hand sidebar for additional RIU-related information.