Pal's house with three phone sockets all thought to be BT installed. Three corded phones all work normally. A bought BT DECT cordless doesn't ring in any of the sockets, but otherwise works. Other phones plugged in at the same time do.
But the DECT phone works normally here along with corded ones.
Anyone guess what the fault might be before I go there and rip out the wiring and start again? It doesn't make any sense to me.
In message , "Dave Plowman (News)" writes
Typing as I think so it may not make sense at this time of night! :-
A corded phone will work OK with a 2 wire circuit, i.e. just the incoming pair. Have the sockets been wired without a master and so no ringing line on pin 3? Only 2&5. Does the DECT base require pin 3?
"> Anyone guess what the fault might be before I go there and rip out the
Have a look at the REN number against each phone. Usual is 1 but can be 1.5 . Limit is total of 4 for house.
If over the limit then one or more phones may not ring - although they should dial out and make and receive calls.
Was going to be my suggestion as well ;-) Sounds like a missing "bell" wire, (i.e. one of the exchange wires shunted via a small bi-polar electrolytic cap (2.2uF 68V working does nicely)).
Check the master socket is fitted, and check the wiring from it uses at least 3 wires. (At risk of soundling like an Abbot and Costellos sketch: Blue/White on 2, White/Blue on 5, and Orange on 3 is the usual setup)
It could be that your friend's installation is missing the ring signal on terminal 3/pin 4, but all his corded phones happen to be of the type that don't require this signal.
-- S.C.
Ahh. Didn't know that.
They were in the house when my pal bought it - but they look BT installed by the wire staples.
I'll check tomorrow. Today ;-)
Slightly OT, but the above wiring notes can be used to your advantage. If you want more phones on a single line than the REN total can normally accomodate, then disconnection of pin 3 (ringing line) to some of the phones will allow this.
The ringing line can be disconnected at the secondary sockets, or (better) short male/female phone cable extensions can be made without this line connected. You can now have (say) three normally wired ringing phones, and a large number of non ringing but otherwise fully functional phones. Providing that you don't live in a baronial castle you will hear at least one of the ringing phones, and can answer any, including the non ringers.
I have run up to eight phone/fax/modems on a single line sucessfully, using this method.
NB: fax machines normally require the ringing line connected NB2 - the ringing off switch commonly found on phones does not have the same function as above described. I suspect that a dummy 1 REN load is substituted for the ringer.
Thought this might be useful.....
Charles F
AIUI, your average electronic phone will have a REN of a lot less than
1, but it's just rounded up. A REN of 1 was needed to drive the old electromechanical bell ccts successfully.
Going over 4 REN rearely causes much trouble unless you really take the piss - although I have known some modems and fax machines that refuse to answer if you do.
Yup. I've got 6 phones and two modems on this line, and all the phones ring ok. Of course the distance to the exchange makes a difference.
Only some will, a considerable proportion of both DECT and wired phones require all 3 lines.
I'd agree you are probably right on this though, either the wiring is wrong or the pin 3 connection has failed, probably in the master socket or wiring between that and the first socket, or the ringing capacitor has failed (rare).
An alternative solution, if it is a wiring fault which isn't east to get at, is to use PABX masters for all the extensions.
Does the DECT phone work when it is the only phone connected? Have your pal got a modem on the same line? It is possible that the other phones are taking most of the ring current so the DECT phone doesn't get enough. I have a Ferranti Flip-phone which will only ring when it's the only phone connected.
Check it in the master socket. If you don't know which it is, it will be the one with a capacitor and other components on the board inside. I would think the house wiring is OK if the other phones work. There could be a problem with the incoming wiring or at the exchange/street cab/remote concentrator unit. It might be worth getting BT to check the line out if it's all their stuff. They won't be responsible for other equipment that's connected, or if the maximum REN (usually 4) is exceeded.
Note that the quoted REN of 4 is the spec that BT aim to reach. In many cases where the line length is not too long the line will actually cope with more than this.
Depends on the phone, some seem to impose significantly less load with the ringer off.
Also note that many modern phones have a REN of far less than 1, but that is the smallest value REN they will mark the phone with.
As a last resort you can also get REN boosters that will take the line values to 8 or more.
It could be that your friend's installation is missing the ring signal on terminal 3/pin 4, but all his corded phones happen to be of the type that don't require this signal.
-- S.C.
Anyway you can always turn off the ringers on some of the phones. You don't always need every phone to ring.
Dave
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