[Gllug] ADSL problem

[Dylan]

On Sunday 27 Feb 2005 23:25 pm, Ben Fitzgerald wrote:
> On Sun, Feb 27, 2005 at 11:02:06PM +0000, Dylan wrote:
> > On Sunday 27 Feb 2005 22:18 pm, Ben Fitzgerald wrote:
> > > On Sun, Feb 27, 2005 at 10:04:47PM +0000, Chris Bell wrote:
> > > > On Sun 27 Feb, Ben Fitzgerald wrote:
> >
> > There is a small amount of circuitry in the "master socket" (the
> > one directly connected to the exchange) on your phone line. This
> > "termination" completes the electronic circuitry of the phone line
> > (in very general and simplified terms.) Extension sockets are
> > daisy-chained to the local side - you can plug in a splitter and
> > extension lead, or split the connection inside the master box, it
> > doesn't matter which.
>
> okay - I think I see where yourself and Chris are coming from. Let me
> just show you my situation. It's as simple as it can get:
>
>   outside
>
>
> ------------------------|--------------------------------
>
>   inside                |
>                  +-------------+
>
>                  |  bt socket  |
>
>                  +-------------+
>
> 		 |   plug-in   |
> 		 |
>                  | microfilter |
>
>                  +-------------+
>
>     +-------------+ |      |  +------------+
>
>     | answerphone |-|      |--| adsl modem |
>
>     +-------------+           +------------+
>
>       +-------+
>
>       | phone |
>
>       +-------+
>
> I have no extentions, just as shown above.
>
> Surely in the above case my answerphone and phone are downstream of
> the filter and should not (if the filter does it's job) see any of
> the adsl spectrum? This is my uneducated guess.

Yes

>
> Why does it matter which side of the termination the filtering occurs
> on?

The filtering in the socket will be higher quality and is not 
susceptible to issues arising from the low quality of phone jack 
connectors.

> Does this affect the line quality or my ADSL link?

It might, especially if you are at the extreme distance from the 
exchange connection.

> 
>
> Why can I hear this high-pitched noise on my answer machine (only
> after the beep to leave a message, BTW - the message can be heard on
> the callers line undistored) and not on regular phone calls.

The electronics in the telephone are likely to be much better than in 
the answerphone. Also, since the answerphone does not make outgoing 
calls it may not pay full attention to the details of that side of the 
line.

>
> Could be my answer machine broke around the time I got ADSL. It +is+
> cheap.

It could be that the answerphone is at fault - I have one handset in the 
house which, if I plug it in to the line with the ADSL and make a call 
it kills the ADSL while the call is open.

>
> I might also add that my phone, about once or twice a day, does a
> kind of whimper, like it's about to ring, then shuts up again. Oh -
> the phone is cheap too!

Hmmm, This is more likely (IME) to be a microfilter issue.

Dylan
>
> Ben
>
> --
> Registered Linux user number 339435

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