[comp.dcom.telecom] Proper Way to Disconnect Ringers on Phones

julian%bongo.uucp@eecs.nwu.edu (julian macassey) (06/23/89)

In article <telecom-v09i0207m04@vector.dallas.tx.us>, pwt1%ukc.ac.uk@
nsfnet-relay.ac.uk writes:
> With reference to the recent conversation regarding REN quotas. Surely the
> simplest solution if there exist too many phones is simply to switch the
> ringer OFF on one or more sets. Many of the cheaper phones have a switch for
> this and for those that do not, simple surgery should do the trick.
>
    Simple surgery is what you need. The OFF switch on telephones,
disconnects the speaker or mechanically stops the clapper on a gong ringer.
The ringing circuit is still connected and so absorbs power. The Telco
wanted it that way, so they could use the ringer circuitry for loop testing.
They also could measure the impedance of your line and tell if you had been
naughty and attached bootleg phones. So if you have too many ringers and the
phones are not ringing or are intermittent, you have to open up and get
at the leads to the ringer or electronic rining circuit. With electronic
ringers (the ones that warble) disabling the 1 uF capacitor will do the
trick.

    Note for UK readers: BT approved phones will not have a cap, it is in
the primary jack. With an approved phone it can be silenced and the ringer
disconnected by removing the lead to pin 3 on the jack (blue with white
stripe). As I recall U.K. phones will handle 4 standard ringers. A warble
ringer on a modern phone usually consumes about half the power of a standard
Plessey gong ringer (old fashioned bell).

    If the moderator wants, I can produce more drivel on wiring U.K. phones
etc. Note that what is public and free information in the U.S. is considered
"proprietary" by British Telecom. I know cos I was foolish enough to ask.
The funny part was I was doing work for them and provided info on U.S.
phones to B T., even gave a training course to some of their R&D folks from
Martlesham.

--
Julian Macassey, n6are  julian@bongo    ucla-an!denwa!bongo!julian
n6are@wb6ymh (Packet Radio) n6are.ampr.org [44.16.0.81] voice (213) 653-4495

davidc%pyr@gatech.edu (David Carter) (06/28/89)

In article <telecom-v09i0210m02@vector.dallas.tx.us> julian%bongo.uucp@eecs.
nwu.edu (julian macassey) writes:
>    . The OFF switch on telephones,
>disconnects the speaker or mechanically stops the clapper on a gong ringer.
>The ringing circuit is still connected and so absorbs power.

The above is not always the case:
I have two phones with electronic ringers.  One, a Radio Shack (ET-100, I
think; discontinued model), included a schematic that clearly showed that
the OFF position of the ring loudness switch electrically disconnected the
ringer circuit.  The other, an AT&T Trimline 210, causes the other phones
in the house to ring more loudly when its switch is set to OFF; so one would
guess that it absorbs no ring power when set OFF.

David Carter