Maximum length straight-through cable

[Audiofight]

Alright. I know that after a certain number of feet, a Cat5 cable must turn into a cross-over cable for what-ever reason (cross-talk reduction or something). I don't care to know the reason, but will gladly accept the information if given.

I just want to know what the cut-off is for a straight-through cable.

Why?

I have been intermittantly (sp?) lossing my IP and connection to the router in our house. It seems to happen very often when using the cable a roommate gave me with the warning that he wasn't sure if it was any good or not. So, I finally got my 1000' spool of Cat5e, ends, tool, boots, and tester. Not bad price, $70 shipped. But, I made a new cable for my supply from router to switch (5-port on my desk for docking station and main rig). It is slightly longer than the previous cable, but a straight-through.

The new cable tests fine, but won't give me any connection. I haven't looked at the old cable yet to see if it was a cross-over or not, but I think I may have exceeded the length and will have to clip one end and switch to a cross-over.

 

[cmetz]

The cross-over doesn't affect the max length.

Max length is 100m, or about 300ft. It IS possible to go longer than that, it's not like things magically stop working at 301ft, but when Ethernet fails, it's often in intermittent and subtle ways, so try not to push the length limit.

Try chopping your ends off and redoing them. Maybe you just didn't do it well enough?

 

[Lord Evermore]

There's no rule about a straight-through cable turning into crossover... A crossover cable is used for one purpose, connected two ports that are wired the same (hub to hub or NIC to NIC) and straight-through is used to connect opposite wired ports (hub to NIC, hub to uplink).

The maximum length according to the spec is 100 meters. This is intended to count as 90 meters of solid-core wire, used for the runs inside walls or ceilings, and the other 10 meters is for patch cables using stranded wire, which connects equipment to jacks that the solid core connects to. Using all stranded wire will reduce the reliability of a full 100 meter run, so you should either make it shorter, or don't use all stranded.

Cat5 is UTP cable, unshielded twisted pair. (Or you can get STP, shielded.) Each pair is twisted together throughout the cable, which is what reduces the crosstalk.

You can look at the ends of the cables, seeing through the clear part of the connector at the colors of the cables. Use google to find the wiring standards for crossover and straight-through Ethernet. Then you'll know what the first cable was, and whether you made the second one to match.

If they do match, then it might be too long, or you might have bad equipment. A cheap tester doesn't guarantee a good cable either, all it does is test whether signal reaches from one end to the other, not so much whether it's a clean signal.