Comments on: Maximum Length of Cat 5 and Cat 5e Network Cables

By: TIm

TIm — Fri, 29 Aug 2008 23:58:16 +0000

Does anyone know how long the CAT 5e cable can carry a normal analog phone signal (residental application)?

By: Of Zen and Computing

Of Zen and Computing — Tue, 04 Mar 2008 16:37:52 +0000

John & Tony Thanks for the excellent follow-ups.

By: JohnMc

JohnMc — Tue, 04 Mar 2008 15:47:27 +0000

I’ll second Tony’s observation and give you one more. Way back in the day we wanted to test what the reality was on a CAT 3 cable. We had a 5k spool of the stuff sitting around. So we crimped both ends down and hooked it up to a pair of ODS hubs. It worked. There was a 8db attenuation and the resend rate went up 5%. Would I do this in practice? Probably not.

Remember one thing the 100m refrain is part of a SPEC. The assumption the authors take in issuing the spec is to assume worst case conditions and still have the signal get thru end to end at the specified amplitude with minimal attenuation. The reality is somewhat different depending on environmental factors. But I do know of a couple of hams who have strung a 1000′ of CAT5 and had it work fine.

By: Tony Lawrence

Tony Lawrence — Tue, 04 Mar 2008 15:10:06 +0000

In reality, how far you can go will vary with the quality of the cable, stuff it passes by, and the equipment it is connected to. Sometimes you can get away with a bit more, sometimes it’s a bit less.

A good tester (and why are you messing with this if you don’t own good equipment?) can tell you how long the cable seems to be – if a 25 foot cable tests out at 100 feet, you’ve got trouble somewhere..

Also, a switch acts as a repeater too.. so if you need a switch out there anyway, the distance beyond now goes up again.. though you can’t just tack on switch after switch after switch.