Impedance; Jitter; Delay - Cabletron Systems 100BASE-FX Cabling Manual

Ethernet Network Requirements
The insertion loss characteristics of a cable are one of the main determinants of
link length allowed by the Ethernet and 10BASE-T specifications. As long as a
UTP cable does not exceed the total insertion loss of 11.5 dB, it may be any length
up to 200 m (656 ft). The 200 meter maximum total length is based on the total
allowable propagation delay in the network, and cannot be exceeded.
NOTE

Impedance

Cabletron Systems 10BASE-T equipment requires that 10BASE-T cables in the
Ethernet network have an impedance within the range of 75 - 165 . Typical UTP
cables used in Ethernet environments have an impedance between 85 to 150 .

Jitter

Jitter may be caused by intersymbol interference and reflection of signal.
Networking technologies that rely on particular timing or clocking schemes may
be affected by jitter due to excessive signal reflection. Any 10BASE-T cable
installation should not exceed 5.0 ns of jitter. If a cable run meets the 10BASE-T
impedance requirements (detailed above), jitter should not be a concern.

Delay

The maximum propagation delay allowable on a 10BASE-T segment is 1
microsecond ( s). If an Ethernet signal is unable to traverse the entire length of an
installed UTP cable run within 1 s, Out of Window (OOW) errors will occur due
to excessive delays between transmission of signals and notification of collisions.
This propagation delay requirement limits UTP cabling to a total maximum
length of 200 m (656 ft).
NOTE
5-2
As longer cables are more susceptible to other limiting factors,
Cabletron Systems does not recommend the installation of
10BASE-T cabling over 100 m in length.
As longer cables are more susceptible to other limiting factors,
Cabletron Systems does not recommend the installation of
10BASE-T cabling over 100 m in length.
10BASE-T