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Appendices
Appendix G: CAT 5 Cable
For optimal video, particularly at maximum distances, LongView extender works best with
Comtran 2819 cable. This cable should be terminated to the EIA (TIA) 568B standard, which is
commonly used for 10BaseT Ethernet. Sending KVM signals over a single CAT 5 cable limits
LongView extender to a 500 foot range. There is not a specific limit on LongView extender refresh
rates, but only rates to 80 Hz are specified. Refresh rate affects maximum extension distance. For
typical distances, refer to Appendix C. For high resolutions, maximum distances are based on a
subjective assessment of the video quality.
Procedure for optimizing cable
If the cable you intend to use is CAT 5 or an enhanced version of CAT 5 (5E or 6 for example),
then the cable's characteristics should be generally acceptable. LongView extender's video tuning
for distance depends upon the cable's loss characteristics and the twist rates. The twist rates vary
from pair-to-pair in a cable in order to reduce crosstalk. Different cable vendors do not use the same
twist rates nor do they put the twist rates in the same order on the four pair. "Better" cable does not
necessarily result in better LongView extender performance because the LongView extender was
not designed for that particular cable.
For short distances of up to 250 feet (depending upon the cable), you are likely to get acceptable
performance with cable other than Comtran 2819 cable. For longer distances it is important to
arrange the pairs according to twist rates so that Comtran 2819 is more closely duplicated. This
means that the wire colors of the four pair may not match the colors as arranged in Comtran 2819.
To optimize your non-Belden cable:
1. Select the pair with the tightest twist rate. This is pair 3, terminated on pins 3 and 6.
2. Select the pair with the second tightest twist rate. This is pair 2, terminated on pins 1 and 2.
3. Select the pair with the next tightest twist rate. This is pair 1, terminated on pins 4 and 5.
4. Select the pair with the loosest twist rate. This is pair 4, terminated on pins 7 and 8.
Take care in terminating the cable according to this procedure. Incorrect termination can damage
the unit. By terminating BOTH ends of the cable as described, the best performance for that cable
will be obtained, but the characteristics of the cable may still cause the video quality to be poor on
long lines. The actual distance that is acceptable for a particular end-user will depend upon many
factors including what applications are being run on the server and the needs of the user.
EIA-568A and EIA568B
LongView extender is designed to work best when the CAT 5 cable is terminated according to the
EIA-568B standard, but other standards exist for terminating CAT 5 cables. The following tables
show EIA-568A and EIA-568B pin assignments. The difference is in the pin assignments of two of
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