All CDQ Prima models use plug-in interface modules that allow you to connect directly to ISDN or to any digital transmission system with available V.35, X.21 or RS422A interfaces. With any 200 Series model, you can install up to three digital interfaces for higher ISDN bit rates or for multiple connections. CDQPrima's broadcast modes allow you to send two independent audio channels to two or more locations, or send the same monaural or stereo program to as many as six locations simultaneously.