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Can cabling cause a phone not to work but a pc will?

philjaeger
Level 1
Level 1

We have an issue at a remote location where we can get a PC to work at a jack but not the phone. If we take the phone back to the switch and plug directly into that port, by-passing the cable, the phone works fine. Anyone have this problem or have any suggestions. We have a tech going out to check the wiring. Thank you.

5 Replies 5

thisisshanky
Level 11
Level 11

I assume you are using inline power. Pins 1,2,3,6 are used for transmit/receive data, while pins 4,5,7,8 for the power. If the cabling guy terminated the cable run from the switch (patch panel) to the wall jack wrong (pins 4,5,7,8) the phone wont power up.

Sankar Nair
UC Solutions Architect
Pacific Northwest | CDW
CCIE Collaboration #17135 Emeritus

droberts
Level 1
Level 1

I believe pins 1,2,3,6 are still used to transmit power if using switch power. The other pins are only used if you have a 'power injector' setup.

All 4 are used for ethernet as well so I'm not sure how your PC could still work. Still probably break out the volt meter to see what's happening.

droberts, is right on the fact that 4,5,6,8 are used only power injector setup. With a inline power switch, 1,2,3,6 should be used for signalling and dc power. Best way to find out is to use a fluke to test the cable run.

Sankar Nair
UC Solutions Architect
Pacific Northwest | CDW
CCIE Collaboration #17135 Emeritus

I'm sorry. If forgot to mention that we are not using inline power. We are using power cubes for these phones. Thanks again for your responses.

jaregalado
Level 1
Level 1

Hi

I think it would be worth checking the length of your cable run with a cable scanner. IEEE Ethernet standards specify 100 mts as maximum length however some equipment still works after you have reached that limit, of course the manufacturer doesn't guarantee it will work.

HTH.

Regards.