On 20/04/2021 16:26, Scott wrote:
On Sun, 18 Apr 2021 09:03:28 +0100, Peter Able wrote:

On 17/04/2021 12:01, Scott wrote:
On Sat, 17 Apr 2021 11:15:53 +0100, The Natural Philosopher
wrote:

On 17/04/2021 10:06, Peter Able wrote:
If all of your extensions are simply connected across the incoming pair,
then induced hum won't just affect one extension.

I thought about that, and then decided as a statement of fact it was
********.

Consider a set of telephone wires all starred from a single point where
they are all shorted together. Telephones are oin te end of each pair.

One of the wires goes through a transformer that is designed to induce
current in it. The telephone on that wire and that wire alone will see
'hum'.

Except that mine are wired as a spur. I am quite surprised the hum
does not go back the way to number 2.


Philosopher, starting with a false assumption is always a bad start, but
star, daisy-chain or hybrid. Would you describe the path(s) of the
induced currents for no handsets lifted and for each handset in turn lifted?

Scott, have you tried swapping around the handsets? Just a bit more
evidence.

No, but I thought of that as I was watching Netflix. I also found out
if I hold the line the buzzing increases !!! Maybe I am acting as an
aerial.


OK - are you going to try swapping? Is that you holding the 'phone or
the power cable? It'd be interesting to see a sketch of the network of
phones - showing any broadband filters. Is each extension used for
phone only, broadband only, or both? Does any of the network still
include a third, "bell" wire?

PA