I don't suppose this can be done with Mikrotik, My question is after a recent incorrect wiring of a RJ45 plug it was strange as the CPE after the POE was working OK - No problem browsing ,logging in with winbox, etc but when i connected the cpe into a internal household router (2.4Ghz) I lose ethernet connectivity to CPE and WEB, remove router and ping direct from laptop to CPE OK - After a long time and replacing Internal router and CPE - we decided to test the cat5 lead and low and behold one side was incorrectly wired cannot recall which pin it was but the fact it worked until we plugged in the internal router really threw us off, as mentioned is there any way for Mitrotik to check the RJ45 wiring, looks like i will be checking the wiring more ofter with the simple RJ45 meter.

You more than likely had a cross over cable where a straight cable was required, or visa versa. It's called Auto MDIX, where certain (newer) network devices will automatically make a straight cable a cross over cable if required.

Your laptop more than likely supports Auto MDIX (and thus automatcally cross the connection), whilst the other CPE device doesn't support it, and hence, didn't get a link.

You more than likely had a cross over cable where a straight cable was required, or visa versa. It's called Auto MDIX, where certain (newer) network devices will automatically make a straight cable a cross over cable if required.

Your laptop more than likely supports Auto MDIX (and thus automatcally cross the connection), whilst the other CPE device doesn't support it, and hence, didn't get a link.

Thanks for the reply, the cat5 lead was custom crimped both ends and i had only one wire crossed over almost sure it was one of the white, with either green stripe or blue stripe but if as you say "Auto MDIX" is there a way to check on a laptop without having to used the led rj45 meter and watch pin1-8 led sequence.

Nope. Not as far as I know. Perhaps in some BIOS' it will show the pins, but I don't recall ever seeing something like this.

Invest in a propper cable tester - they're cheap enough these days.

As mentioned it was strange but it has taught me a lesson and in future I will use the basic RJ45 pin to pin meter to test.

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