ISL3232E/ISL4221E/ISL4223E RS-232 Interface ICs Renesas Electronics ISL3232E/ISL4221E/ISL4223E RS-232 Interface ICs are 2.7V to 5.5V powered RS-232 transmitters/receivers that meet ElA/TIA-232 and V.28/V.24 specifications, even at VCC = 3.0V. The devices provide ±15kV ESD protection (IEC61000-4-2 Air Gap and Human Body Model) on transmitter outputs and receiver inputs (RS-232 pins).