How to protect RS-232 serial connections

The RS-232 port often represents the "Achilles heel" of otherwise power-protected computer installations.

Nov. 8, 2012

A recent white paper from APC-Schneider Electric explains specific power protection issues related to RS-232 cabling. The document contends that the RS-232 port often represents the "Achilles heel" of computer installations which are otherwise well protected by UPS systems and other power protection equipment.

The document notes that in an interconnected network of computer equipment, RS-232 serial data connections are frequently used for connections to terminals, printers, modems, and in the case of so called "zero slot" LANs, for network wiring connections. However, the RS-232 port on any device also represents a path into the device for damaging noise and transients. The types of transients which can enter via an RS-232 port originate from a variety of sources. These sources include inter-system ground noise, telephone line surges, and wiring faults.

Authored by Neil Rasmussen, the paper explains in detail the special vulnerabilities of RS-232 cabling, and describes appropriate protection and mitigation techniques.

Download the white paper here.

See also:NEMA Surge Protection Institute launches educational website