The Intersil ISL3178AE is ±15kV IEC61000 ESD protected, 3. 3V-powered, single transceiver that meets both the RS-485 and RS-422 standards for balanced communication. This device has very low bus currents (+125µA/-100µA), which presents a true "1/8 unit load" to the RS-485 bus. This allows up to 256 transceivers on the network without violating the RS-485 specification’s 32 unit load maximum, and without using repeaters. For example, in a remote utility meter reading system, individual meter readings are routed to a concentrator via an RS-485 network, so the high allowed node count minimizes the number of repeaters required. Receiver (Rx) inputs feature a "Full Fail-Safe" design, which ensures a logic high Rx output if Rx inputs are floating, shorted, or terminated but undriven. Hot Plug circuitry ensures that the Tx and Rx outputs remain in a high impedance state while the power supply stabilizes. The ISL3178AE is a half duplex version. It multiplexes the Rx inputs and Tx outputs to allow transceivers with output disable functions in an 8 Ld package.