The TRS211 device consists of four line drivers, five line receivers, and a dual charge-pump circuit with ±15-kV ESD protection pin to pin (serial-port connection pins, including GND). The device meets the requirements of TIA/EIA-232-F and provides the electrical interface between an asynchronous communication controller and the serial-port connector. The charge pump and four small external capacitors allow operation from a single 5-V supply. The devices operate at data signaling rates up to 120 kbit/s and a maximum of 30-V/μs driver output slew rate.

The TRS211 has both shutdown (SHDN) and enable control (EN). In shutdown mode, the charge pumps are turned off, V+ is pulled down to V_CC, V- is pulled to GND, and the transmitter outputs are disabled. This reduces supply current typically to 1 μA. EN is used to put the receiver outputs into the high-impedance state to allow wired-OR connection of two RS-232 ports. It has no effect on the RS-232 drivers or the charge pumps.