We have an old magneto telephone bell connected into the telephone wiring which we've found useful as the sound carries better than the modern phone sounders. I've got it shunt connected between pins 3 and
5 on the conventional telephone socket, that is between the "white with blue markings" wire (Pin 5) and the "orange with white markings" wire (Pin 3), i.e in series with the ringing capacitor.It has always worked fine until we got a couple of new phones a year or two back. These have the automatic 1571 message detection which means the phone goes off-hook every now and again to check for the special dial tone. On one phone, BT Relate 3000, you can switch off the 1571 detection, whereas the other phone, a BT Decor 1200, has the
1571 feature permanently on.The problem is, when the phones go off-hook, the bell goes ding, presumably because the sudden change in line voltage goes through the capacitor and into the bell.
The bell is an older lower resistance unit (about 1000 ohms total for the coils). I've wired in extra resistance and gone as high as 12k ohms. The bell still rings quite well, but the ding is also still there although reduced in level.
Does anybody have any ideas if this can be fixed, or do I just need to replace the bell with an electronic sounder?
Thanks,
Hugh