Programmable data access arrangement having combined command signals

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. A safety barrier device is provided within the DAA in the transmission pathway for each of the multiple parallel command signals, where this arrangement allows parameter command signals to be transmitted through the safety barrier devices and then branched to various parameter-controlled circuitry after passing through the safety barrier devices, thus reducing the number of safety barrier devices required to provide electrical isolation for the modem.