sundance-communications.com/forum Forums Wiring - Telecom Carriers - Trunks & Services Cabling Telephones Systems Wiring 568a or b configuration

We took over an existing job and noticed that some cables were terminated 568 a and some b. Network was working fine that way. Mos. later, we can't get on internet. Cable modem is working perfect, once we plug network into modem, can't get on internet. Could it be the mixed a and b config. All cables test out fine. Don't think this could crash network all of a sudden.

If connected devices use a single pair of wires (Blue/White), mixed cabling won't manifest itself as that pair lands on the same positions with both conventions. Once you add more pairs, then the trouble begins. Either way, pick a convention and use it from end to end.

568B is most common in the US as it was developed by AT&T (Western Electric).

If terminated the same on both ends it won't matter.

"Cable modem is working perfect, once we plug network into modem, can't get on internet."

You will need to explain a few things, using industry-standard terms. First, I suspect that this not a wiring problem at all, since wires do not stay up late at night to conspire to drive us crazy. Unless a human has gotten his fingers into the situation, wires that worked in the past will work in the present. You are correct when you say "Don't think this could crash network all of a sudden."

That said, please explain what you mean by "cable modem is working perfect." How did you test it? What did you plug into it to determine that it is working "perfect."

Next, what do you mean by "we plug network into modem"? A network, which generally consists of many wires going to many locations, needs a router/switch to create the ports necessary. How did you plug a network into a modem? Have you by-passed the router (assuming there is one) and patched directly from the modem output jack to a single computer's input jack?

Finally, as the other guys have stated, you can use whatever color code you like, as long as the same code is used at both ends of a particular cable.

A (the old Merlin wiring standard) is awful, b is better, just to keep it straight as to which one to use the most.

We plugged laptop directly into modem, Time Warner cable did this, nothing else was plugged into modem. Was able to get onto internet.

Then came out of modem,into Araknis switch, came out of switch and into rest of network. We do Control 4 and Sonos Audio.

Have feeling, someone plugged a wrong device into an Ethernet port, causing this problem.

If it's just a switch, then you need a router, if attaching more than 1 cable, THEN use a switch for any extra ports.

EDIT: Forgot to mention, up here when we swap out or add a a router, we have to reboot the modem on a cable connection so that it sees it. Being on cable down there it might be the same as well.

B was the old Definity/Merlin standard.

-Hal

Time Warner cable modems are all in one. Modem, Router, Switch, and AP.

Does the network work with the modem unplugged? Meaning can you print to a network printer or such.

Not sure about printing. I bet network does not work. I will be on site this week