line conditioner

Definition of line conditioner in The Network Encyclopedia.

What is Line Conditioner?

Any device that is used to prevent undesirable electrical signals from damaging computer, networking, or telecommunication equipment and to guard against data loss due to electrical noise, sags, and surges. Sometimes called a line shaper, a line conditioner can also ensure that the parameters of the signal remain within specifications for the medium or interface being used, even over excessively long or noisy transmission lines.

By maintaining signal integrity, line conditioners can allow communication devices to function at higher throughput rates.

How It Works

Line conditioners contain circuitry that enables them to filter out noise caused by electromagnetic interference (EMI) and other sources. They also contain isolation transformers that electrically isolate the circuitry from unwanted DC voltages, impedance-matching circuitry for reducing unwanted signal reflections, and surge suppressors to guard against high-voltage surges (6000 volts or more) caused by lightning strikes and power failures. Line conditioners can also correct sags (drops) in voltages caused by momentary brownouts, but they are not meant to replace or supply power during a power loss. They often include fault indicators and audible alarms.

You can use line conditioners in the following places:

  • In power supplies and in uninterruptible power supply (UPS) systems (power conditioners) to protect computers and networking devices from AC surges coming through power lines.
  • In local area networks (LANs) to protect hubs, routers, and other networking equipment from EMI and unwanted noise coming through the networking cables, and to maintain the integrity of network data signals.
  • In offices to protect modems, telephones, fax machines, and other equipment by filtering out electrical surges in phone lines and to reduce noise so that the devices can operate at their nominal throughput speeds.
  • In WAN links for protecting CSU/DSUs (Channel Service Unit/Data Service Units) and access servers connected to Integrated Services Digital Network (ISDN), T1, and other copper telecommunication lines against EMI surges. T1 lines must have line conditioners at regular intervals to ensure the integrity of the signal transmitted over the line.

Line conditioners can often improve analog modem transmission speeds, enabling high-speed modems to function at their maximum transmission speeds over noisy telephone lines in the local loop.