return loss measures the amount of reflected signal energy resulting from impedance changes in the cabling link.the nature of 1000base-t renders this measurement very important; if too much energy is reflected back on to the receiver, the device does not perform optimally.

    unlike 10base-t and 100base-tx, which use only two of the four pairs of wires within the category 5, 1000base-t uses all four pairs of the twisted pair. make sure all wires are tested — this is important.

    factors that affect the return loss are:

    · the number of transition points, as there is a connection via an rj-45 to another connector, a patch panel, or device at each transition point.

    · removing the jacket that surrounds the four pairs of twisted cable. it is highly recommended that, when rj-45 connections are made, this is minimized to 1-1/4 inch (32 mm).

    · untwisting any pair of the twisted-pair cabling. it is important that any untwisting be minimized to 3/8 inch (10 mm) for rj-45 connections.

    · cabling or bundling of multiple category 5 cables.this is regulated by ansi/eia/tia-568a-3. if not correctly implemented, this can adversely affect all cabling parameters.