nospam wrote in
:

In article ,
lonelydad wrote:

there was once a time when you couldn't do that in your own home.
the phone company only allowed their phones, even with rj11 jacks,
and they could tell if there were additional extensions you
weren't paying for, which is why many phones were designed to not
be detectable.

The ringer on each phone/device puts a load on the line. If that load
gets too big the ringers won't work properly and other bad things
micht occur. That's what the big fuss was about with Ma Bell. They
decided that the best way to keep that from happening was to control
the devices connected to the line. These days, every landline device
has a ringer equivalence number on the label. The sum of all
connected devices should not be greater that four, if I remember
correctly.

nothing bad occurred with an additional phones, other than the phone
company wasn't being paid for extensions.


You just didn't have enough devices connected to hit the wall.

Per Wikipedia:

The total REN load on a subscriber line is the sum of the REN loads of
all devices (phone, fax, a separate answerphone, etc.) connected to the
line; this number expresses the overall loading effect of the subscriber
equipment on the central office ringing current source. Subscriber
telephone lines are usually limited to support a load of 5 REN or less.

If the total allowable ringer load is exceeded, the phone circuit may
fail to ring or otherwise malfunction. For example, call waiting, caller
ID and ADSL services are often affected by high ringer load. 20th century
equipment tends to contribute to a larger REN than new equipment.

Some analog telephone adapters for Internet telephony require analog
telephones with low REN, for example, the AT&T 210 is a basic phone which
does not require an external electrical connection and has a REN of 0.9B.