Internet, Networking, & Security Home Networking Recommended Standard 232 (RS-232) Ports and Cables By Bradley Mitchell Writer An MIT graduate who brings years of technical experience to articles on SEO, computers, and wireless networking. our editorial process LinkedIn Bradley Mitchell Updated June 01, 2019 Piotr Wytrazek / Getty Images Home Networking The Wireless Connection Routers & Firewalls Network Hubs ISP Broadband Ethernet Installing & Upgrading Wi-Fi & Wireless Tweet Share Email RS-232 is a telecommunications standard for connecting certain types of electronic equipment. In computer networking, RS-232 cables were commonly used to connect modems to the compatible serial ports of personal computers. So-called null modem cables could also be connected directly between the RS-232 ports of two computers to create a simple network interface suitable for transferring files. Today, most uses of RS-232 in computer networking have been replaced by USB technology. Some computers and network routers possess RS-232 ports to support modem connections. RS-232 also continues to be used in some industrial devices, including newer fiber optic cable and wireless implementations.