atcomsystems.ca/forum Forums VOIP Phones & IP PBX Networking cat5 line

hello guys, im a phone guy who runs network cable sometimes. i ran a cat5 run from ground floor to the roof, the air cond people needed it for the equiptment. they put the conduit from the roof to the 4th floor phone room and from there it was streight down to the second floor. at that point i had to go across the hall to the first floor phone room. the line tested good when i was done. been a few months ago. now the maintence man for the building said they dont always get connected and the guys who put in the equiptment say its a bad line. i will be going to check it monday. at this point i want to use my tester on it and then put it on a network at the first level and see if i can get online with a laptop on the roof. any ideas to help me trouble shoot this one. thanks dave

whats the total distance involved and what is it used for ?

I doubt that this is your usual ethernet cable so don't bother with the laptop stuff. It's not that critical. I would just use a tester that does a wiremap and checks for shorts and opens. Be sure and wiggle the terminations and check for corrosion. If it tests OK then the ball is out of your court.

-Hal

Yes, the Ethernet spec limits the distance to 100m.
Although you can run a cable longer over 100m and it may still work (PHY may be over-designed), but it is not guaranteed.

In additional to testing by a tester alone. You can leave you computer running "Ping" to another device on the internal network overnight, and check how many packets got lost. Use the max. length packet (1518 bytes) to ping.

Are you responsible for the wire or connection as well? If you are responsible for the wire only, do your test to confirm it's not the wire. Then send it back to the hvac company telling them it's not you. And ask them why they believe it's the wire and not their equipment.

Do you know for certain the cat5 is being used for networking? Make sure to check the connectors if modular. Vibrations can cause loose connections.

I did a job running a cat5 cable for some hvac equipment on the 28th flr to the bsmt engineers office. They were using it as a serial connection. Either 422 or 485. The only thing they requested was that certain connections use a twisted pair. I don't remember if it was using a single pair or 3 wires. They asked me for the wire but I also did the connection to screw terminals.

in not sure of the length but it well under 300 ft. i am responsible for the cable. the customer says the equiptment people can connect their computer at the equiptment on the roof but not in the phone room using my line. they did request cat 5 and thats what i put in for them. i go out monday to check my line. i will post details. dave

Dave,

It looks like you're working right in my back yard (I'm in Upland), so why don't you give me a ring when you get into spots like this.

Whether CAT5/e is appropriate or not will depend on whether your cable run is for the air conditioning controls themselves, or rather for a larger, Ethernet-based energy management system. I suspect that you're been contracted for the latter.

I'll send you a PM with my email address and phone #.

If they can connect at the equipment end, then it's NOT your cable or connections. Sounds like they don't know how to connect at the patch panel or that they're tring something else in the phone room & blaming you.

Intermittent issues can be a big pain. Do you have a cable certifier? If not, take Tim up on his offer for help. Whenever another vendor is blaming their problems on my cable I test and print the cert.

Send a copy of the result to everyone concerned. When they see all the squiggly lines in the test parameters and the "Pass" icon in the upper corner of the test result it shuts them up every time.

I would certify the cable as it is; then I would re-terminate the connections and certify again. I guess you could have a poor punch resulting in intermittent connectivity?

made it to the job today and tested the line. it came up good. i have plugs at both ends so i put on jacks and jumpers just in case they didnt have a solid connection. he tried it and got better response but didnt make final communication. he feels at this point the company who sold the equiptment to them needs to make some adjustments. it will take 2 weeks for them to show up so its the waiting game. will post results. dave