POE over UTP Cable

eng_ahmedas

Dear Friends
I wish you are fine ....... I have a question and i want you to help me understand it ..... We all know that POE is very useful when connecting IP Phones, Video or wireless device to Switch ..... Also you know from our CCNA Study that external power like generators cause noise and distorstion to our data transmission and it is recommanded that you install your UTP cable away from any power source
Although it is recommanded to install my UTP cable away from any power source, I used the spare wires (4,5,7, to power any POE device .... Doesn't that affect data transmission on wires (1,2,3,6) and caus noise and distortion ????
Thanks in advance

bermovick

Woo! Electrical theory. It's been a few years (like 20), but I think I remember this.

Pretty much the distortion (induction) is the EM field thrown off that you're referring to. Having the pairs of wires twisted serves to balance (cancel out) that field so as to lessen the impact to other nearby wires.

eng_ahmedas

Dear bermovick
Thanks for your replay .... I think also that only the AC current which is inducted by the EM field that has effect on data and cause distoration but he DC current (which used in case of POE) has no effect on data ....... Is that true ????? Whats your opinion ?????

Thanks in advance