IDEAL INDUSTRIES, Inc. 1-2
testing is critical because the cabling installer does not necessarily
know what types of devices are going to used on the network.
For example, a network that has been certified to meet the
requirements for Category 5e performance can support various
applications such as 10/100/1000 Mbps Ethernet, 155Mbps ATM,
RS-488, RS-232, and many more. However, it is often the case
that in any residential or commercial network, Ethernet devices will
be the only type used.
SIGNALTEK uses the IEEE 802.3ab (Gigabit Ethernet) standard
as a reference for cable performance testing. Rather than a
traditional certification test where frequency-based parameters
such as Near End Crosstalk (NEXT) and return loss are measured,
performance or qualification testing, as it is sometimes called, is a
Bit Error Rate Test (BERT). Data packets are sent down the cable
to the remote handset then re-transmitted back to the display
handset where the number of lost or errored packets is counted.
The results are displayed for the user to get an instant view of the
cable’s performance. A cable performance test is marked as a
“pass” or “fail” based on the IEEE 802.3ab parameters which
specify the number of error packets allowed in a given test time.
The IEEE (Institute of Electrical and Electronic Engineers) has
created a set of standards that allows hardware and software to
perform over a variety of media. Unlike the EIA/TIA which specifies
cabling limits to support various communications protocols, the
IEEE creates the actual protocols. The 802 structure addresses the
following transmission protocols:
? 802.3 Ethernet over a physical medium (twisted pair)
? 802.4 Token passing over a Bus topology
? 802.5 Token passing over a Ring topology
? 802.11 A family of wireless signaling standards (Wi-Fi)
? 802.12 Shared media standard that will support Ethernet and
Token Ring on the same physical network
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