In article , Dave W
writes
On Fri, 6 Dec 2013 10:38:33 +0000, fred wrote:

It's worth noting too that if a unit (phone/base-station/ringer) places
any ringing load on the line then the minimum REN recorded against it
must be one (no 0.5 or 0.25). As DECT base stations merely load the line
to detect the ringing rather than power the ringer itself then they may
present a far lower load, permitting you to break the rules by exceeding
an official REN of 4.

I can't believe that. The phone has to look like 1 REN otherwise the
exchange will think the line is broken. Or maybe I'm wrong, and the BT
master socket looks like 1 REN with nothing plugged in?

There is no requirement to fit a phone to any of the installed sockets
and not loading the bell is not a fault condition.

Automated test circuitry will look for the combination of a 1.8uF cap in
series with a 470k resistor but not for a ringing load.
--
fred
it's a ba-na-na . . . .