LAN (cat5) interference

[Deceased]

Hi folks,

Got a strange one.

1 chap in the office gets (or rather, has sometimes sporadic, sometimes permanent) interference (buzzing) on his phone. Its a basic analog phone fed over CAT5 with an adaptor.

Another chap nearby also gets the same problem - sometimes at the same time as the other fella but invariably not on his own.

So far to troubleshoot I've tried the following:

• Replaced the computer
• Replaced all leads to do with the computer and the phone (including the headset to base unit lead on the phone itself)
• Replaced the phone.
• Replaced the adaptor
• Had the electrical sockets checked by an electrician
• Patched him in via a different floor point - was ok at first but problem has come back....

As far as I can tell the wiring back in the patch cabinet doesn't run near anything that could give off a signal.

The weird bit is that when it was doing its (sporadic) phase - it "sometimes" also affected the other guy - who sits nearby but isn't wired through the same floor point.

I've pretty much proved it's the wiring as when I plug his phone into the switchboard directly (its an Avaya IP unit) the phone is clear so its definitely the wiring.

I don't really want to pull out the patching in the cabinet if I have to (though I'm a little "resigned" to the fact that i think i'm going to have to).

Have any of you lot had a similar issue and what tools do you use to test? - can you recomend any?. Little point trying a standard lan tester (all that proves is that voltage can go down each wire and where they end up.

[Nomad]

mobile phone nearby?

[Deceased]

Originally Posted by Nomad

mobile phone nearby?

Heh - nope. Already thought of that. Seems some models of blackberries are notorious for causing this kind of thing.

Whats weird is - its doing it right now, and the other guy across the way is also getting the noise on his phone. If I switch off the 1st guys computer - the problem vanishes.

Which is why I changed the computer for another and the power, network leads etc.

I'm thinking that it must be a bad earth somehow/somwhere but the electrician couldn't find anything outwardly wrong.

[Inertiaman]

Or it's the cable as you suspect - and the noise is dropping when his network connection is inactive.

Run a fresh cable over the floor to a different and distant-as-possible floorbox/wallsocket to test.

[Deceased]

Originally Posted by Inertiaman

Or it's the cable as you suspect - and the noise is dropping when his network connection is inactive.

Run a fresh cable over the floor to a different and distant-as-possible floorbox/wallsocket to test.

Yeah could try that.

I think i might just bite the bullet and repatch his connection in the cab - its the only way I can rule out the physical wiring between the cab and his floor plate (we've already tried changing the RJ45 socket in the floor plate as well).

[burundi]

Can you physically move the computer base unit further away from the guys desk to see if that helps?

Tried a small UPS on the PC to filter the electric supply?

Tried running the power for the PC from a different wall socket?

[Deceased]

Originally Posted by burundi

Can you physically move the computer base unit further away from the guys desk to see if that helps?

Tried a small UPS on the PC to filter the electric supply?

Tried running the power for the PC from a different wall socket?

Physically move machine = no (its a different one anyway as 1 swapped it out when this started happening).

UPS - don't have any that I can use.

Power = looks like thats the next best choice I think.

[burundi]

Originally Posted by Deceased

Physically move machine = no (its a different one anyway as 1 swapped it out when this started happening).

Could be a issue with a batch of machines so swapping the machine isn't a guarantee that it's not the machine at fault, given it stopped when you shut it down it's your best bet so far. It could even be the CPU, case fan or some other component that only starts causing interference under high load.

When it's happening can you physically move the base unit away from the desk (whilst running) to see if the interference changes?

[Deceased]

Originally Posted by burundi

Could be a issue with a batch of machines so swapping the machine isn't a guarantee that it's not the machine at fault, given it stopped when you shut it down it's your best bet so far. It could even be the CPU, case fan or some other component that only starts causing interference under high load.

When it's happening can you physically move the base unit away from the desk (whilst running) to see if the interference changes?

Well we are ascending to new levels of weirdness now.

At this moment in time - his new machine is switched on and happily ticking along.

His phone is absolutely fine - no problems.

The chap in question isn't in the office.....

I'm beginning to think that it might be "him" or something about/on him.... ie. a another phone or some other electrical device.

[burundi]

Vibrating butt plug! it's the only answer that makes any sense.

[Nomad]

or you work with qui?

[Deceased]

Originally Posted by Nomad

or you work with qui?

Wot? qui has a butt plug?

Actually. Problem solved - fecking monitor - or rather its power supply

[qui]

I accidentally the whole thing.

[Nomad]

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