How serial isolators protect against data line surges

RS-232 is a common standard for serial communication. Unprotected RS-232 ports can be vulnerable to power surges. A serial isolator can help resolve this problem and protect sensitive data equipment from disruption, damage or data corruption.

By Max Burkhalter
July 13, 2021
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RS-232 is a common standard for serial communication. Unprotected RS-232 ports can be vulnerable to power surges. A serial isolator can help resolve this problem and protect sensitive data equipment from disruption, damage or data corruption. 

How RS-232 works
According to CommFront, RS-232 lines connect Data Terminal Equipment (DTE) such as a desktop computer, with Data Communication Equipment (DCE) such as a modem, for transmitting data packets between the the two. A straight-through can connect DRE to DTE, or DTE to DCE. Signals are connected on a one-to-one basis. RS-232 connects the Ground of different devices together, correcting an "Unbalanced" connection which is more susceptible to noise, and limited to a distance of around 15 meters.

RS-232 is often utilized in LAN networks, which can experience harmful power surges that travel along both electrical and voice/data communication lines. The copper wire used in most modern installations is highly conductive, and electricity takes the path of least resistance. The resulting surge or spike can cause considerable damage to the infrastructure of a LAN network, and be costly and time-consuming to fix. 

Using data-line devices to protect LAN systems from unpredictable backdoor surges
LANs connects computers and other devices and systems such as telephone, data, video and security both in and between buildings. However, each connection creates an attractive path for data-line surges to enter and travel through the system. Equipment that is protected by AC power-line suppressors and an uninterruptable power supply (UPS) is still vulnerable, since data-line surges can enter the network through any unprotected "backdoor," such as a printer, modem line or peripherally networked device.   

Installing data-line surge suppressors such as serial isolators between LAN data cables and equipment network ports can help protect against many common electrical disturbances. Cabling install recommends you use isolators at network distributions points, punchdown blocks and building cable entry points, as well as next to hubs, routers and other LAN equipment. This isolates the device and protects it against power surges, or electrical transients. Transients are caused by lightning, electrostatic discharge and ground loops. LAN data-line surge suppressors are designed to divert damaging surges before they reach critical equipment.

Clamping to disrupt power surge and divert energy flow
A UPS alone is not sufficient to protect communications and data transmission lines. When the UPS dumps the surge into ground, the surge can recognize any data line as the path of least resistance. The surge blows through computer chassis and fries the communications card in the computer. Many surge devices blow due to improper installation that doesn't follow specifications. Implementing serial isolators as another line of data line device protection allows you to divert or shunt this transient voltage away from the data line, and to the building ground.

This clamping function creates a choke point above which transients are eliminated. The breakover or breakdown voltage assigned determines at what level a protector begins to conduct and when the device`s failsafe disconnect activates, meaning that the isolator will shut down and effectively stop the transient from reaching the DTE devices. The isolator sacrifices itself and burns out to protect the equipment in this last ditch failsafe maneuver. This will only work effectively if all AC, data and telecommunications products have a common ground.

Causes and consequences of data surges
Causes of data-line surges can be natural, originating from static buildup or a lightning strike. They can also be technical failures, such as ground loops, faulty wiring or AC circuit variation between buildings and connected facilities. The result of a data surge can range from slow transmission or corrupted data, to a locked up system, or protection faults. On worst case scenarios, components can fail, including serial ports, network interface cards, modem/ fax cards or even entire motherboards.

Using serial port isolators can prevent a direct surge or transient power blip from damaging your system. Perle provides a full range of serial isolators. Contact us today to learn how to better protect your systems and devices.


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