Abstract: An apparatus for reducing electromagnetic interference on signals being communicated through one or more communications conductors is disclosed. The apparatus of the present invention is preferably situated in a communications circuit having a first area for receiving one or more communications conductors and an intermediate ground, and a second area having a reference ground. The apparatus includes one or more first capacitors, where each first capacitor is coupled between a communications conductor and the intermediate ground, and a second capacitor coupled between the intermediate ground and the reference ground. In preferred embodiments, the first area is a telephone network voltage (TNV) area, the second area is a secondary extra low voltage (SELV) area, the first capacitors are regular high voltage capacitors, and the second capacitor is a Y capacitor.

Abstract: A data access arrangement (DAA) for interfacing a modem with a telephone line which requires only one safety barrier device for providing electrical isolation of the modem from the telephone line for both a ring detection signal and a remote device hang-up detection signal transmitted from the DAA to the modem. The DAA utilizes the same combined circuitry to transmit both the ring detection signal and the hang-up detection signal to the modem. The single safety barrier device is selectively connected to either ring detection circuitry during an On-Hook mode or remote hang-up detection circuitry during an Off-Hook mode by a selectively operating a relay switching device. With this arrangement, an improved DAA is provided having a combined circuit configuration for communicating ring detection information to the modem during the On-Hook phase and communicating remote hang-up detection information to the modem during an Off Hook phase, thus minimizing the size, cost, and complexity of the DAA.

Abstract: A universal data access arrangement (DAA) for interfacing a modem with a telephone line which may variably control its parameter settings to meet the interface requirements for telephone networks in various countries. The parameter settings are programmed into the universal DAA by multiple parallel command signals received from a connected modem. Each of the command signals is concurrently transmitted to a plurality of parameter-controlled circuits in the DAA, where each parameter-controlled circuit may interpret the received command signal to correspond to a different parameter setting. This allows different circuits of varying functionality to be separately programmed with different parameter settings using the same command signals received by each of the circuits.