What is REN

Ringer Equivalence Number (REN)

REN measures the load a device places on the line when ringing. A normal BT line will support a REN of at least 4, in other words at least a total of 4 phones/fax/modems should work on any line so long as their REN figures added together don’t exceed 4.

The REN is normally found on a label at the base of the machine
(near the green approval symbol).

In practice you can quite often exceed this number because devices with a REN of 1 may actually have a real REN of only a fraction of 1.This is an anomaly of the test procedure used. Moreover many lines can drive a REN of more than 4.
Note that some elderly fax and answering machines can have very high REN’s (and they really are high!). If some or all of your phones fail to ring or some ring very anaemically then its possible you have exceeded the REN. Try unplugging devices until they work.
You can get REN Boosters which will increase the ringing capacity of a line if desired, although if you get to this stage you should probably be thinking of installing a small PABX.

On June 5th, 2016, posted in: REN by

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