Near End Cross Talk, Length | NETGEAR GS108T-100NAS specs

GS108T Smart Switch Software Administration Manual

If installing new cable, NETGEAR recommends using Category 5e cable, since it costs about the same as Category 5 cable. If using the existing cable, be sure to have the cable plant tested by a professional who can verify that it meets or exceeds either ANSI/EIA/TIA-568-A:1995 or ISO/ IEC 11801:1995 Category 5 specifications.

Length

The maximum distance limitation between two pieces of equipment is 100 m, as per the original Ethernet specification. The end-to-end link is called the “channel.”

TSB-67 defines the basic link, which is the portion of the link that is part of the building infrastructure. This excludes patch and equipment cords. The maximum basic link length is 295 feet (90 m).

Return Loss

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 onto 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 cable, 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 through 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. NETGEAR strongly recommends 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 settings.