Date: Wed, 7 Nov 2001 14:28:58 +0100 From: "Anthony Atkielski" <anthony@atkielski.com> To: "Bill Moran" <wmoran@potentialtech.com>, <questions@FreeBSD.ORG> Subject: Re: Welders causing dial-out to fail Message-ID: <008a01c16790$2908f910$0a00000a@atkielski.com> References: <3BE81735.7020302@potentialtech.com> <003f01c166f0$45e05b00$0100a8c0@MOBILE2> <3BE8380C.7060302@potentialtech.com>
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It may not be the proximity of the equipment itself, but the proximity of electrical wiring to telco wiring or computer equipment somewhere in the building. Also, all the computer and telco equipment should be on circuits well isolated from those supplying the heavy equipment, and they should be further isolated with battery-backup UPS units. Your problem sounds like simple intereference right on the telephone line (if it's audible to you, it's practically unusable to a modem), but you may eventually experience other problems with hardware if you have glitches in the power supply. Disks are said to be especially sensitive to power supply changes; it reduces their life expectancies, apparently. ----- Original Message ----- From: "Bill Moran" <wmoran@potentialtech.com> To: "SNF" <lists@stevenfettig.com> Cc: <questions@FreeBSD.ORG> Sent: Tuesday, November 06, 2001 20:20 Subject: Re: Welders causing dial-out to fail > In response to a few other similar responses, I thought I'd throw in some > more details: > The proxy server is physically located in the wiring closet where the phone > lines are. There is only about 5' of phone line from the proxy to the main > telco jack. The welders are on the other side of the building: > > telco conn. > +-----+-----+-------------------------+ > |proxy| | | > +-----+ | | > | | | > | | | > | office | | > | | | > | | | > +-----------+ | > | | > | welders | > | | > +-------------------------------------+ > > I don't know whether this may mean different things to different people, > but it doesn't (from my viewpoint) seem to support the "shield the wire > from proxy to telco will solve the problem" angle. > The ceiling of this place is metal girders, and some of the electrical > runs through the ceiling, so I'm wondering if the ceiling is getting > charged or something and acting like a huge antenna that just transfers > the interference throughout the rest of the building. > > This may be an interesting problem to solve ... I've got a lot of ideas > to try, so thanks to everyone for the suggestions. > > -Bill > > SNF wrote: > > Bill, > > > > I agree with Michael's response. I am the IT guy for a manufacturing > > facility that just happens to also use a lot of resistance welding > > equipment - on top of that, loads of MIG and TIG welding aparatii... When I > > first got here, one of the first problems to deal with was the horrible > > internet connection (similar setup - FreeBSD pppd, etc). When we determined > > it wasn't the ISP, we started looking at the setup. By simply moving from > > typical CAT3 phone wiring to some decent grade CAT5 wiring, the problem went > > away. I thought it was going to require shielded cabling, but it didn't. > > In a new facility I am working on, I am puting in shielded just to be sure. > > There I have more problems with the actual lines from the telco than with > > the internal lines we installed. Because of the limited price differential > > between high quality CAT5E and shielded CAT5E, I would definitely re-outfit > > the dial-up line with shielded. Long term - if cost is an issue - it will > > simply hold up better to a welding environment than any non-shielded cable > > (assuming what you are buying is of some quality). The type of modem you > > are using, quality of the dial-in service, etc. can all play a part in this, > > but I would guess that a cable change would make a nice difference. > > > > > > Hope this helps, > > SF > > > > ----- Original Message ----- > > From: "Bill Moran" <wmoran@potentialtech.com> > > To: <questions@freebsd.org> > > Sent: Tuesday, November 06, 2001 11:00 AM > > Subject: Welders causing dial-out to fail > > > > > > > >>This may be a little off-topic ... > >>I have a client who I installed a FreeBSD proxy server for. > >>It uses pppd to dial out on demand. Right from the start, the > >>client has been having problems with the reliability of the > >>dial-out. To make a long story short, after a lot of testing > >>and speculating, we determined that its electric welders in the > >>shop causing the problem. There are five resistance welders in > >>the shop and when all five are working, the Internet connection > >>is simply unusable. If two or three are in use, the Internet > >>is slow, the connection drops a lot and has to dial 2 or 3 times > >>to get a connection. If nobody is welding, the Interenet > >>connection works perfectly. > >>The interference exists on all 4 phone lines, it's audable at > >>times on the voice lines (but never very bad) and has never > >>been bad enough to disrupt the fax machine. > >>We had the phone company (Verizon) come in and they basically > >>said, "Our wiring isn't the problem, you may want to have this > >>building rewired." > >>Does anyone have any experience with this kind of thing? Rewiring > >>the building is pretty much cost-prohibitive. Verizon did install > >>a noise filter at their junction box, but the improvement is very > >>minimal. > >>We're searching a few avenues for a solution, one being the > >>manufacturers of the welding machines, but I thought I'd put the > >>question out to this list and see if anyone else has worked through > >>and found a solution for a problem like this. > >> > >>TIA > >>-- > >>Bill Moran > >>Potential Technology > >>http://www.potentialtech.com > >> > >> > >>To Unsubscribe: send mail to majordomo@FreeBSD.org > >>with "unsubscribe freebsd-questions" in the body of the message > >> > >> > > > > > > > -- > Bill Moran > Potential Technology > http://www.potentialtech.com > > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-questions" in the body of the message > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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