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Ups Recommendation

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I am thinking in investing in one.

I got 2 modems burned out, and i am worried about my hardware.

I don't need expensive one, some economy class about 100$ or less.

Thanx guys

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Well, UPS and modems are probably a different story. You should have a UPS to protect your hardware, though if it is not at least line-interactive it won't do much more than a surge protector, hardware-safety wise (data is another story).

We mostly own APCs, though all of our new purchases have been Tripp Lite.

Most modem frying comes from 'phone lines that are too hot. The 'phone company will do this because telephones are more resistant to hot power and it tends to result in less audio quality complaints. They will also vary the voltage at will, again because for an analog voice line there is no issue.

If your 'phone company offers "data certification" for the line and it is not prohibitive in cost, this will help. A lot. At least, it does for Verizon.

You should also get something like this:

http://www.apc.com/resource/include/techsp...CCountryCode=US

That specific product is not exactly what you want, we use PTEL2 & PTEL4s, but they don't look like that so I must have ended up in the APC subcategory - but the protection idea is the right one.

Yes, I even use them in my home - for PVRs, phones, everything.

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Modems is usually destroyed by HVD on the telephone line.

But a decent UPS is good anyways : )

/casa

Exactly, but the PTELs properly installed will prevent this. I ran into this with some dial up routers we used about 6-7 years ago - their built in in modems could only go to 220 and Verizon regulalry used 250+. Needless to say those modems did not last long, but when I installed a bank of PTEL4s and patched everything through those it was fine.

I do the same for 10/100 NIC & their CAT5 products - think about what sort of potential a few 100ft of wire can pick up - but they are limited to 100MHz, so aren't great for GBe.

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I do the same for 10/100 NIC & their CAT5 products - think about what sort of potential a few 100ft of wire can pick up - but they are limited to 100MHz, so aren't great for GBe.

I think copper LAN's only show the different in

the mains system between the two sides.

It's probably safe when you're cabling in the

same building (if not in an industry).

But don't connect the shield at both ends.

BTW ether has at least 1,5KV media strength.

/casa

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That's good to know - and probably why their product line for CAT5 seems less robust than for telco.

Still, all of our gear is in Anvil cases - we take our entire office on the road - and on a production site, with several different power setups, guys dropping all sorts of wire of who knows what kinds all over your stuff, distros, etc. I figure I'm safer by being paranoid about power. I've seen job sites where the ground for some legs had 100s of volts on it - nice when you wire together gear, some on that leg, some on another. And don't even get me started about generator power.

Anyway, maybe my experiences of seeing audio guys get knocked on their ass by loops make me overly cautious, but then again the reason I keep getting gigs is because my gears always works.

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For those who don't know,

UTP cabling used in networking is different from audio and coaxial cabling in two major respects. First, twisted pair transcievers use differential input and output stages. As there is no electrical connection between either of the two wires and the ground of each system, both systems remain electrically isolated. The only thing that matters is the potential difference between the wires, and not the voltage of each wire relative to ground. The correllary to this is that as there is no ohmic connection between computers connected via twisted pair (ignoring any other sources), ground loops are impossible over twisted pair cabling.

This is different from audio and coaxial cabling where the outer conductor, or sheild is generaly connected to the frame of each system, creating an ohmic connection between them, allowing for the creation of ground loops in the system. Though grounding is always important from a safety standpoint, it becomes additionaly so in these systems for proper operation.

-Chris

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As far as UPS's......i've done very well by buying older UPS's off ebay and then purchasing new batteries through an electrical distributor like Digikey or Mouser. I was able to scratch together a smartUPS 2200 as well as 3 additional battery cabinets and all fresh batteries for under $1000 this way. I also aquired a SmartUPS 650 with fresh batteries for $80 this way.

In newer models (post ~1996) that were designed to have their batteries replaced by end users, you just reuse the existing cabling, pop in the new batteries, and you're done.

Of course, it's not for everyone.

-Chris

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I've seen job sites where the ground for some legs had 100s of volts on it - nice when you wire together gear, some on that leg, some on another.

Sounds like sourced from different power stations : )

You can get pretty nasty spikes in a typical industrial

environment but IMO very rare cases avg above 10 V.

What can happen is the other stuff around you getting

a potential offset refering ground. And if so there's

never a good idea to measure it with a DVM due to

the high input impedance.

One example, consider a three phase mains cabling.

When all is ok you will measure N:0V P1,P2,P3:115V

but if one fuse drops (lets say Phase 2) you may get

N:0V P1,P2,P3:115V. As soon as you attach a load on

them the DVM goes N:0V P1,P3:115V P2:0V.

Though 100'th of Volt measured the ground potential

may very well been around 0V.

/casa

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I'm not really sure what you're getting at casa...

Are you refering to a floating ground?

-Chris

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If I follow him - and pardon me here, but if I get this wrong then good because I'd like to get it right - he's talking about the 3-phase cams that feed the distro (actually usually the iso then the distro). A false positive on a ground problem can be the result of one of the hot lines being cold. I am not sure if that applies if you are metering on the other side of the distro, though. So your 115/120 will look that way with a meter? But not all legs, right? So will it really be a false positive, or will the "hot" leg and the "cold" leg have different ground levels?

Hmm, trying to explain it convinces me I'm missing the middle part. The EICs I hire are usually video guys, so I'm not sure if they know this, either.

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An older post of mine about UPSs and power protection/AVR technology here. Too long to repost/retype.

If battery backup isn't critical, APC and others make extremely good surge protectors that offer all the power regulation of a good UPS. Look for ones that have AVR (automatic voltage regulation) for both spikes and brownouts. Most are good for use with devices that use huge amounts of power, like laser printers.

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Based on that post, and since we're so far off topic anyway (sorry $100 UPS guy), I think the thing to really go for beyond the AVR & line interactivity is the true on-line UPS. You get a good, clean sine wave (of course you start at $1K & quickly go up) and never have to worry about the wall at all - it is just to keep the batteries juiced.

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Actually, in the thread I linked above, a link was posted to "www.refurbups.com", which sells, obviously, refurbished UPSs. They come with new batteries and have a perfect rating at resellerratings.com.

As I type this, they sell a 700VA APC Smart UPS for $89. It provides good AVR and a true sinewave output (though this seems overrated, honestly).

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As I type this, they sell a 700VA APC Smart UPS for $89. It provides good AVR and a true sinewave output (though this seems overrated, honestly).

Ah, wow, that's a great deal on that unit. We probably have about 10 or 12 of those, and I think just replacing the battery is around $50.

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4 years ago while I was working as resident "techno-dude" at a private school, the school was moving all of its administrative duties to portable trailers while a portion of the school was being rebuilt. After getting all the gear into the portable trailers, I took a break for lunch and instructed the office people NOT to plug anything in because the electricians had been having some problems. About 20 minutes later I get a frantic call from the office people saying "all the computers are smoking!" I return to find that the office people plugged their computers in and the el-cheapo electrician hired to hook the power up to the portable classrooms jumped three 110 lines together and sent it into the portable classrooms. The only things to survive were 3 viewsonic monitors and 1 HP LaserJet 4 out of 10 complete computer setups and 4 laser printers. I'm not sure a UPS would've been able to handle that but that very day we went out and bought a sizeable APC ups for each workstation. Never been without them since.

Chris

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Ah, wow, that's a great deal on that unit.  We probably have about 10 or 12 of those, and I think just replacing the battery is around $50.

Right, so rather then replacing the battery in your :::used::: UPS for $50, it makes sense to buy a whole nother :::used::: ups for $80.

I don't get it :-)

-Chris

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I am thinking in investing in one.

I got 2 modems burned out, and i am worried about my hardware.

I don't need expensive one, some economy class about 100$ or less.

Thanx guys

APC is been around for quite a while, I have two APC's. You should also get some decent inexpensive surge protectors (APC) for you home entertainment system. in case of sudden outages, one way to prevent damage to circuit board components of your electronics.

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Ah, wow, that's a great deal on that unit.  We probably have about 10 or 12 of those, and I think just replacing the battery is around $50.

Right, so rather then replacing the battery in your :::used::: UPS for $50, it makes sense to buy a whole nother :::used::: ups for $80.

I don't get it :-)

-Chris

Who would do that? Unless I suppose it had a warrantee or something.

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Ah, wow, that's a great deal on that unit.  We probably have about 10 or 12 of those, and I think just replacing the battery is around $50.

Right, so rather then replacing the battery in your :::used::: UPS for $50, it makes sense to buy a whole nother :::used::: ups for $80.

I don't get it :-)

-Chris

No, he had already purchased the units, he was just stating that a simple battery refresh cost almost as much as the price of the whole refurbished unit. It *does* make sense to get the refurb unit for $89 rather than the new unit for $300 if you don't have a UPS at all, especially when the price range is <$100

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