The Studio Technologies Model 45A is designed to interface a 2-wire full-duplex party-line intercom circuit with a 4-wire audio circuit associated with a matrix intercom system. Other specialized audio system interfacing applications can also be supported. Applications for the Model 45A include television sports and special event broadcasting, theme park and theater installations, corporate events, and industrial testing environments.
The Model 45A provides a full-featured 2-channel interface which includes two hybrid circuits with automatic nulling capability. The analog hybrid circuitry provides excellent audio quality and high return-loss. For flexibility, the Model 45A can be powered by the connected 2-wire party-line circuit or by means of an external source of 24 Vdc. When powered by an external source the Model 45A is capable of supplying DC power to the 2-wire intercom circuit, allowing direct operation of devices such as user beltpacks. Audio level meters provide confirmation of system performance during setup and operation. Standard audio connectors are used for all input and output signals. The Model 45A's enclosure has a "1/2-rack" 1U form factor and weighs less than two pounds, making it well suited for use in portable applications. Alternately, using one of the optional rack-mount front panels, one or two Model 45A units can be mounted in a single space of a standard 19-inch rack enclosure or one unit can be mounted in a speial 10.5-inch rack.