Thank you for reply. How is it possible that doorbel cause only 1-2 CRC errors, doesn't cause synchronization break, doesn't lower SNR margin? In the radio doorbell is scarcely audible.

there is no sign that the bell is mains powered but it could be

I don't understand. How could it be else than mains powered?

Best regards
konrado5

Edited by konrado5 (Thu 06-Feb-14 22:36:55)

Not uncommon for bells to have a few D cell batteries in the plastic case. As I said without knowing more and seeing an install (or someone having the same exact same model hard to tell. Also no obvious sign of a mains feed into the bell unless that is what the junction boxes are doing

Short amounts of noise can just create errors, and if the ADSL is not particularly busy the modem will tolerate these few errors. Also the onscreen display of SNR margin is not updating at 50 times a second more like once every five or ten seconds.

In reply to a post by MrSaffron:

Not uncommon for bells to have a few D cell batteries in the plastic case. As I said without knowing more and seeing an install (or someone having the same exact same model hard to tell. Also no obvious sign of a mains feed into the bell unless that is what the junction boxes are doing

Thank you very much. Your knowledge is very helpful.

I think the doorbell is connected to mains. However, I'm curious if the mains causes any interference at the time when doorbell doesn't ring. If this installation causes only 1 CRC error when someone rings it isn't profitable to change it. I'm not sure if doorbell interfere by odd installation or rather by router power supply. At the logitech computer speakers I hear little crack when doorbell rings but speakers are connected far away from doorbell rings.

Furthermore, doorbell causes error only on download (never on upload).

Best regards
konrado5

Edited by konrado5 (Thu 06-Feb-14 23:09:32)

Back EMF is what used to provide the spark in a car engine. Even a low voltage source can provide quite a spark.

In reply to a post by konrado5:

How could it be else than mains powered?

I would have thought it unlikely that doorbells are main powered, at least in UK. I've been using the same (wired) battery operated doorbell (in diff houses) for over 40 years. More modern ones are wireless, but still battery operated.

Ah, I just found a battery/mains transformer operated on here: http://doorchimesuk.co.uk/catalog/product_info.php?c... . So that entry wiring could be mains, the round box a transformer and the oblong box the bell chimes.
EDIT: But where is the bell-push circuit?

Out of interest, is your main photo with all that wiring and boxes of a floor or a wall?

Edited by XRaySpeX (Thu 06-Feb-14 23:29:13)

What if the bell-push is switching the mains?

In reply to a post by BatBoy:

What if the bell-push is switching the mains?

It very probable. When the doorbell rings I hear crack in the computer speakers. Similarly, I hear crack when I turn light off.

Out of interest, is your main photo with all that wiring and boxes of a floor or a wall?

Wall

But where is the bell-push circuit?

It is on the far side of connect terminator.

Edited by konrado5 (Thu 06-Feb-14 23:37:53)

Remind me not to ring your doorbell when it's raining.

In reply to a post by BatBoy:

What if the bell-push is switching the mains?

Can it do that? I'm not in a hurry to push that bell-push!

Seriously, that example says 'Illuminated bell push buttons with transformer power only.'

In reply to a post by konrado5:

But where is the bell-push circuit?

It is on the far side of connect terminator.

Of course!. That's what the connector block is for. It makes or breaks the 12v supply from the transformer.