Guidelines for Protecting RS-232 Serial Connections

RS-232 connections are an integral part of serial-to-Ethernet networks. Most Ethernet networks are exposed to harsh environments and meet high-volume data transmission demands. As an active part of such networks, RS-232 serial devices and their connections are susceptible to destructive parameters. Since RS-232 is an essential component of modern serial-to-Ethernet networks, the vulnerability of RS-232 cables cannot be ignored.

It needs to be protected against power issues. Without proper RS-232 protection measures, the possibility of electrical hazards, equipment damage, and sudden network failures may be inevitable. That is why protecting RS-232 wiring is critical. This article discusses different protection techniques for RS-232 wiring in electronic devices or serial Ethernet networks.

RS-232 Overview

RS-232 is a signal transmission standard. RS stands for Recommended Standard and 232 refers to TIA-232-F standard. This standard discusses the communication capabilities of TIA-232-F standard on serial communication equipment. Equipment working under RS-232 standard enables signal transmission between data terminal equipment (DTE) and data circuit-terminating equipment or data communications equipment (DCE). RS-232 cables are commonly used for serial communication or serial to Ethernet communication.

The RS-232 cable connects the DTE and DCE via the DB9 connector.

RS-232 serial connection protection technology

By using the following techniques, you can protect your RS-232 connections from power surges and other power-related problems.

• Short-range modem: A CPU or server connected to Ethernet via a serial port. These fiber-optic modems can protect against surges up to 3 to 6 kilovolts. The short-range modem is integrated between the CPU or server equipment and the DCE via twisted pair cables that conform to the RS-232 serial communication standard.
• Data Line Protection: Data line protection is achieved by integrating a shunt device between the DTE and DCE. These shunt devices are often called data line protectors. In serial communication, data transmission is in the form of electrical signals, so surge issues must be addressed. The shunt is able to withstand surges and will not damage the serial-to-fiber converter.
• Fiber Optic Link: Fiber optic technology is an effective solution for protecting RS-232 connections. Fiber optic links are a solution to data surges and ground loop noise. Fiber optic links transmit data in the form of light pulses. Therefore, the problem of power surges is solved. In addition, fiber optic transmission is not affected by noise, electromagnetic frequencies, radio frequencies, etc. Fiber optic, as an advanced technology, can adopt features such as transmission authentication to prevent equipment damage. Transmission authentication can include device pairing using handshake protocols. In this way, data will only be sent when the receiving device of the DCE allows it to be sent. This solves the problem of data surges and data leakage at one time. In addition, since data transmission is in the form of light instead of electrical signals, the problem of electric shock is solved.
• Isolation transformer: Isolation transformers provide shielding for the DCE against external noise. While these devices do not protect the RS-232 connection from ground noise, they can prevent the effects of external noise.