The MAX3322E/MAX3323E 3.0V to 5.5V powered EIA/TIA-232 and V.28/V.24 communications interfaces are designed for multidrop applications with low power requirements, high data-rate capabilities, and enhanced electrostatic discharge (ESD) protection. All RS-232 inputs and outputs are protected to 15kV using the IEC 1000-4-2 Air-Gap Discharge method, 8kV using the IEC 1000-4-2 Contact Discharge method, and 15kV using the Human Body Model. The MAX3322E/MAX3323E have pin-selectable 5k/high-impedance RS-232 receivers. These devices are capable of receiving data in high-impedance mode. In multidrop applications, one receiver has a 5k input resistance, while the other receivers are high impedance to ensure the RS-232 standard is observed. Logic control permits selection of the functional mode: high impedance or RS-232 standard load. The transmitters are enabled by logic control to allow the multiplexing of the inputs to a single UART.