Date: Tue, 6 Nov 2001 10:45:18 -0900 From: Beech Rintoul <akbeech@anchoragerescue.org> To: Bill Schoolcraft <bill@wiliweld.com>, Bill Moran <wmoran@potentialtech.com> Cc: <questions@FreeBSD.ORG> Subject: Re: Welders causing dial-out to fail Message-ID: <20011106194519.49147D8@nebula.anchoragerescue.org> In-Reply-To: <Pine.GSO.4.33.0111060920220.28168-100000@corten8.billschoolcraft.com> References: <Pine.GSO.4.33.0111060920220.28168-100000@corten8.billschoolcraft.com>
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On Tuesday 06 November 2001 09:09 am, Bill Schoolcraft wrote: > At Tue, 6 Nov 2001 it looks like Bill Moran composed: > > wmoran->This may be a little off-topic ... > wmoran->I have a client who I installed a FreeBSD proxy server for. > wmoran->It uses pppd to dial out on demand. Right from the start, the > wmoran->client has been having problems with the reliability of the > wmoran->dial-out. To make a long story short, after a lot of testing > wmoran->and speculating, we determined that its electric welders in the > wmoran->shop causing the problem. There are five resistance welders in > wmoran->the shop and when all five are working, the Internet connection > wmoran->is simply unusable. If two or three are in use, the Internet > wmoran->is slow, the connection drops a lot and has to dial 2 or 3 times > wmoran->to get a connection. If nobody is welding, the Interenet > wmoran->connection works perfectly. > wmoran->The interference exists on all 4 phone lines, it's audable at > wmoran->times on the voice lines (but never very bad) and has never > wmoran->been bad enough to disrupt the fax machine. > wmoran->We had the phone company (Verizon) come in and they basically > wmoran->said, "Our wiring isn't the problem, you may want to have this > wmoran->building rewired." > wmoran->Does anyone have any experience with this kind of thing? Rewiring > wmoran->the building is pretty much cost-prohibitive. Verizon did install > wmoran->a noise filter at their junction box, but the improvement is very > wmoran->minimal. > wmoran->We're searching a few avenues for a solution, one being the > wmoran->manufacturers of the welding machines, but I thought I'd put the > wmoran->question out to this list and see if anyone else has worked through > wmoran->and found a solution for a problem like this. > wmoran-> > > In my old shop http://wiliweld.com/calbody we had the wires not only > covered for sparks but for "noise" since we had CAD programs running > on computer driven burning/punching machines. > > If this is only a few phone lines I'd imagine running them through > some "noise" proof conduit, possibly PVC of some sort till you get > out of the area, or possibly see if the interference is coming from > the actual welding contacts or the machine(s) internal panels, then > you may enhance the shield by wrapping the source of noise. > > AM radios were useless in the shop, but FM was fine. etc. etc. > > Hope something helps here. Use shielded cat5 for your phone lines, from your main terminal. Welders generate incredible amounts of RFI (ie wipes out AM radio) that same noise is also trashing your dialout lines. Shielded cable, or shielding the cables in metal conduit is the only way you're going to solve this problem. Beech -- Micro$oft: "Where can we make you go today?" ------------------------------------------------------------------- Beech Rintoul - IT Manager - Instructor - akbeech@anchoragerescue.org /"\ ASCII Ribbon Campaign | Anchorage Gospel Rescue Mission \ / - NO HTML/RTF in e-mail | P.O. Box 230510 X - NO Word docs in e-mail | Anchorage, AK 99523-0510 / \ ----------------------------------------------------------------- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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