Using Existing Phone Lines for IP and PoE Transmission in Surveillance Systems.

Garrett Savage

On February 3rd In Video Surveillance
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Electrical spark between  two insulated copper wires

Running new cable can be a costly and time-consuming part of any video surveillance installation. Fortunately, IP adapter technology has innovated to the point where virtually any existing telephone cable that has at least two continuous copper conductors can be utilized to transmit and receive Ethernet signals and Power over Ethernet, (PoE). This opens up a world of new possibilities for the implementation of IP surveillance cameras and other devices. One such possibility is the use of telephone lines for the transmission of IP signals and PoE.

Telephone cables are one of the most common types of metallic cables, and they have been installed in virtually every home, enterprise and institutional buildings to date. The ability to use these legacy connections for IP and PoE transmission dramatically reduces the time and cost associated running new cable for video surveillance installations.


Existing telephone cables can be utilized as a pathway for IP and PoE transmissions.

The diagram above demonstrates how transmitters and receivers can be used to provide IP and PoE connectivity over an existing telephone cable.  The PoE power can be supplied by either a head-end PoE enabled switch as is shown in the top illustration. Alternatively, PoE can be injected into the head-end device to provide the needed power to the remote end device.

One advantage of this technology is that these devices are transparent to the network which means they are not repeaters and do not have MAC or IP addresses.  This simplifies installation as no programming of the devices is required.  Once properly connected the LEDs light up and the devices are doing their job.

Specifically, the Nitek EL1551U Transmitter & Receiver set can transmit IP and PoE over two-conductor wire up to 500 meters. The two devices are also NEMA TS-2 environmentally rated.   These devices are perfect for transmission of IP and PoE over telephone cables, and they are often used to update older analog emergency telephone stations to VOIP devices.

For any advice, you may need on your next project ADI’s Systems, Sales, and Support Team is here to help. You can contact the ADI Systems Support group at 1.800.ADI.SYS1

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