Re: adsl parameters: ideal readings?

"martin goose" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed) o.uk...
> On Tue, 21 Jul 2009 16:07:25 +0100, Peter Crosland wrote:
>
>> There are no ideal readings as such. An ADSL circuit is a dynamic thing
>> that varies second by second so all you have is a snapshot at a
>> particular instant in time.
>
> Therein lies the problem unless you monitor the S/N ratio and sync speed.
> Even then what sort of variation in S/N is 'normal'?
>
> I am currently monitoring these values and finding wide swings in S/N
> both up and down. I have done all the usual in house stuff to eliminate
> problems with my kit, but looking at a trace for the last 36 hours shows
> a 15dB improvement to 27 dB at one point and two drops from 15dB to about
> 6 dB which caused a resync in each case.

Therein lies the fundamental problem with ADSL. Telephone wires were never
designed to carry data so the electronics at each end have to adapt to suit
the varying line conditions. It's a credit to clever engineering that it
works at all.

If you need a reliable connection (i.e one that is designed to be reliable,
and meet a performance specification) then you will have to install optical
fibre.

--
Graham J

On Tue, 21 Jul 2009 17:46:42 +0100, Graham J wrote:
>
> If you need a reliable connection (i.e one that is designed to be
> reliable, and meet a performance specification) then you will have to
> install optical fibre.

People always go on about fibre and how wonderful it is. "Speed of light"
and all that. Anyone still using IR to transfer files ?

"R Johnson" <(E-Mail Removed)> wrote in message
news:4a660be8$0$2492$(E-Mail Removed)...
> On Tue, 21 Jul 2009 17:46:42 +0100, Graham J wrote:
>>
>> If you need a reliable connection (i.e one that is designed to be
>> reliable, and meet a performance specification) then you will have to
>> install optical fibre.
>
> People always go on about fibre and how wonderful it is. "Speed of light"
> and all that. Anyone still using IR to transfer files ?

Line of sight limitation, I think ...

--
Graham J

R Johnson wrote:
> On Tue, 21 Jul 2009 17:46:42 +0100, Graham J wrote:
>> If you need a reliable connection (i.e one that is designed to be
>> reliable, and meet a performance specification) then you will have to
>> install optical fibre.
>
> People always go on about fibre and how wonderful it is. "Speed of light"
> and all that. Anyone still using IR to transfer files ?

Given that I think most of the BT backbone is IR over fiber, I would
guess so, yes.

On Wed, 22 Jul 2009 10:34:27 +0100, The Natural Philosopher wrote:

> R Johnson wrote:
>> On Tue, 21 Jul 2009 17:46:42 +0100, Graham J wrote:
>>> If you need a reliable connection (i.e one that is designed to be
>>> reliable, and meet a performance specification) then you will have to
>>> install optical fibre.
>>
>> People always go on about fibre and how wonderful it is. "Speed of
>> light" and all that. Anyone still using IR to transfer files ?
>
> Given that I think most of the BT backbone is IR over fiber, I would
> guess so, yes.

Trust you to know that ;-) You could have let me had a moments fun there
whilst people pictured sending files between a mobile phone/pc with an IR
dongle....