The MAX563 is a +3.3V-powered EIA/TIA-562 transceiver with two transmitters and two receivers. Because it implements the EIA/TIA-562 standard, the MAX563 communicates with RS-232 transceivers, yet consumes far less power; this makes it ideal for battery-powered, hand-held computers. And, the MAX563 guarantees a 116kbps data rate while maintaining ±3.7V EIA/TIA-562 signal levels, which makes it compatible with LapLink software. An on-board charge pump converts the +3.3V supply to the ±6.6V needed to produce the EIA/TIA-562 output voltage levels. Four 0.1µF charge-pump capacitors and a bypass capacitor of similar size are the only external components required. When the MAX563's charge pumps and transmitters are shut down to save power, the receivers remain active to continuously monitor signals from external devices (for example, ring indicator from modems). The two receivers' outputs can be enabled and disabled independently of the shutdown function to allow two ports-generally of different types-to be wire-OR connected at the UART.