The ADM485E/ADM487E/ADM1487E are 5 V, low power data transceivers with ±15 kV ESD protection suitable for half duplex communication on multipoint bus transmission lines. They are designed for balanced data transmission and comply with Telecommunication Industry Association/Electronics Industries Association (TIA/EIA) standards RS-485 and RS-422. The ADM487E and ADM1487E have a 1/4 unit load receiver input impedance that allows up to 128 transceivers on a bus, whereas the ADM485E allows up to 32 transceivers on a bus. Because only one driver is enabled at any time, the output of a disabled or power-down driver is three-stated to avoid overloading the bus.