Bing found the following results
Arduino RS232 | Arduino Tutorial - Arduino Getting Started
Arduino & RS-232 Protocol
How to read from and write to rs232 device from/to Arduino
How to interface Arduino with RS232 communication protocol: …
Serial - Arduino Reference
Arduino RS-232: Serial Communication and Data Interfacing
Arduino Communication To and From a Serial RS232 Device
Universal Asynchronous Receiver-Transmitter (UART) - Arduino …
Arduino Serial Communication Tutorial - DeepBlue
How to interface Arduino with RS232 communication protocol