Cat5E for Voice FREE cabling and networking Helpdesk
 Question by David Takanashi posted 16 Oct 2002
 Cat5E for Voice

I have installed CAT5E for data/voice network. I teminated the RJ45 jacks following the 568B color schema. I terminated the data to a patch panel which works fine. I then terminated the voice cables to a 66 block using the following colors, blue/blue-white, orange/orange-white, green/green-white/ and brown/brown-white down the block. I am using an Intertell digital system. My problem is when a user accidentally plugs a data cable in the telephone jack on the wall it blows a fuse. Do you have any idea why it is blowing fuses and what are your recommendations?


 Answer by Dmitri Abaimov posted 16 Oct 2002
Dear David,

This is because Ethernet uses pairs #2 and #3, in some NIC cards unused pairs #1 and #4 are shortened and connected to the ground. Intertel system, on the other hand, uses either just #1 or #1 and #2 with #1 used for power. Then you connect power to the ground, the fuse can't stand it. I would recommend to label jacks clearly, preferrably with colored plastic icons so that it's easy to tell a phone one from a data one.

Dmitri Abaimov, RCDD

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