The LTC1544 is a 4-driver/4-receiver multiprotocol transceiver. The LTC1544 and LTC1543 form the core of a complete software-selectable DTE or DCE interface port that supports the RS232, RS449, EIA530, EIA530-A, V.35, V.36 or X.21 protocols. Cable termination for the LTC1543 may be implemented using the LTC1344A software-selectable cable termination chip or by using existing discrete designs. The LTC1546 includes software-selectable cable termination onchip. The LTC1544 runs from a 5V supply and the charge pump on the LTC1543 or LTC1546. The part is available in a 28-lead SSOP surface mount package.