"The cable is terminated in either the T568A scheme or the T568B scheme. Canada and Australia use the T568A standard, and the United States commonly uses T568B scheme. It really doesn't make any difference which is used as long as you use only one of the standards so all connections are the same at your location to avoid confusion and potential problems. Mixed cable types should not be connected in series as the impedance per pair differs slightly and may cause signal degradation."
Cat6 Category 6 cable - Wikipedia, the free encyclopedia