Ringer Equivalency Number A number which represents the ringer loading effect on a line. A ringer equivalency number of 1 represents the loading effect of a single traditional telephone set ringing circuit. Most modern telephones probably will have a REN lower than 1. The total REN expresses the total loading effect of the equipment on the ringing current generator (FXS). The REN of a Digium FXS board is 5 (representing "extension," i.e., parallel-connected telephones). The actual number of devices on the line may be greater than the REN limit, if their respective individual RENs are less than 1. See also: FXO, FXS
(Ringer Equivalency Number) - A number representative of the maximum voltage that can be carried by a single Central Office (CO) phone line. In most cases, the CO offers a maximum REN of 5. The amount of REN required by an individual analog telephone is usually listed on the bottom of the phone. If REN is exceeded it will result in the loss of ring capability in certain phones.
Ringer Equivalency Number 1 REN = The energy to ring 1 Plain Old Telephone. The REN number can be found on the FCC label on the device. The total ringer load on a line is equal to the sum of all the REN numbers of all the telephone devices connected to the line.