Cable Basics
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Building Your Own Cables
Cables that you build must comply with standard cable specifications and network
requirements. Cable length, cable type, cable and connector attenuation, and other
factors affect the overall performance and reliability of your network.
For example, using a cable length longer than that recommended in industry
standards or interface specifications, or using a cable type that is unsuitable,
considering the cable environment (temperature, electrical noise, radio-frequency
[RF] emissions, and other factors) may degrade network performance and
reliability.
For additional information about maximum cable length and other factors, consult
the appropriate EIA, IEEE, CCITT, or ISO specification, standard, or
recommendation. Some examples include:
• IEEE 802.3 10BASE-T Specification (10 Mb/s CSMA/CD over twisted pair)
• IEEE 802.5 Specification (token ring)
• X3T9.5 Single-Mode Fiber PMD Specification (FDDI)
• EIA RS-449/RS-422A Standard
• EIA RS-232-C Standard
• CCITT V.10/V.11/V.28/V.35 Recommendations
• CCITT X.21 Recommendation
See also the manufacturer’s specifications for any cables or connectors you want
to use. Specifications for attenuation per unit length of cable, and for connector
insertion loss, are useful in helping you to determine the maximum amount of
signal loss (and, therefore, the maximum distance) allowable between two directly
connected network devices.
The physical interface on each device (for example, the connector on an Ethernet
link module in a Nortel Networks router hardware platform) determines which
industry specification, standard, or recommendation you need to consult for
guidelines on how to customize your cables.
To assist you in determining which industry document you need to consult, the
description for each cable in this guide includes an “Industry Interface Type”
description.
