On 02/18/2019 12:10 PM, Mark Lloyd wrote:
On 2/17/19 9:56 PM, nospam wrote:

[snip]

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

IIRC, the phone company could detect them by the additional ringer load.
A phone would not be detectable if the ringer was disconnected. This
would often be done if you had too many extensions (you don't need them
all ringing anyway).

When I was young, I spend a lot of time looking at the Radio Shack
catalog, and remember those 4-prong plugs. I never saw them in use. What
I did see a lot of looked like a 1/4-inch headphone jack. However, there
was no jack but for some reason the installer had used a cover plate
with a hole in it instead of a blank plate.


Back in the day when I was young and lived on a farm in Saskatchewan we
had wall mounted Phones with a crank up generator to power the ringers,
We were on a 3 party line , our call was 2 long and 1 short ring, one
neighbor a mile away was 2 short rings, the other one half a mile away
was 1 long and 1 short ring.
If you wanted to connect to any other line you gave 1 extra loooong ring
which hooked you up with "Central" 11 miles away, you told her whom you
wanted to call and she would patch you through on her jack field and
patch cords which was tied to every phone in the municipality.
I don't remember what the Phone generator ring voltage was but the audio
circuit in each phone was powered by 2 #6 cells for a total of 3.2
volts, The whole system was very reliable and never gave much trouble.

Rene