The MAX250 and MAX251 chip set form the heart of a complete, electronically isolated, RS-232 dual transmitter/receiver. By combining many functions on two chips, the cost and complexity required for an isolated digital interface is greatly reduced. Four low cost optocouplers, four capacitors, a diode and a small pot-core type transformer are all that are required to complete a 19.2k baud transceiver. Faster data rates are possible by using high speed optocouplers. In addition to the driving and receiving circuitry for the optocouplers, the chip set includes a push-pull transformer driver to supply power to the interface's isolated side. Other convenient features include single +5V operation, a low power shutdown mode, and output enable control for three-state operation. The MAX250 and MAX251 are supplied in 14 lead DIP, 14 lead small outline and 20 leadless chip carrier packages. The MAX252 has all the required components for RS-232 communication in a single package.