This design, based on a Maxim MAX220 RS-232 driver/receiver IC, allows you to increase the number of USARTs (universal synchronous, asynchronous receiver/transmitters) available on a microcontroller.

Renesas' new RX23E-A Solution Starter Kit jumpstarts accurate analog evaluation for industrial automation and measurement equipment ...

This article explores methodology for adding RS-485 capability to a PC’s RS-232 serial port by implementing automatic direction control.