ringer equivalence number
- Its abbreviation is REN. A number which indicates the load a telephone, answering machine, fax, or similar device, places on a telephone ringing circuit. If such a circuit is capable of driving a total of five REN, then five telephones with a REN of one may ring simultaneously, or 4 with a REN of 1.25, and so on. However, if, for instance, three devices each with a REN of 2 were connected to this line, then one or all may fail to ring in the event of an incoming call. A REN may also indicate the total load a given telephone line can drive in terms of the RENs of multiple connected devices.