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2.2 10BASE-T NETWORK DESIGN GUIDELINES: MR9T
Transceivers and network devices that connect to the MR9T must
meet IEEE 802.3 standards. Your network must meet the following
IEEE 802.3 10BASE-T Twisted Pair requirements when connecting
devices with the MR9T.
•
Segment Length - The IEEE 802.3 10BASE-T standard
requires that 10BASE-T devices support a 100 meter (328
feet) minimum link length using 22-26 AWG unshielded
twisted pair wire. As a general rule, if your link meets the
allowed limits for insertion loss and impedance, links up to
125 meters (410 feet) are possible. Higher quality low
attenuation cables may be required for links greater than
125 meters. Due to cable delay, the maximum link length is
always limited to 200 meters, regardless of cable type.
•
Insertion Loss - The maximum insertion loss allowed for a
10BASE-T link is 11.5 dB at all frequencies between 5.0 and
10 MHz. This includes the attenuation of the cables,
connectors, patch panels, and reflection losses due to
impedance mismatches in the cable segment.
•
Impedance - Typical unshielded twisted pair cable
impedance is 85 to 110 ohms. Shielded twisted pair cables,
such as Type 1 cable, can also be used. Type 1 cable
impedance is typically 150 ohms. This increases the signal
reflection caused by the cable. Since the cable is shielded,
signal reflection has little effect on the received signal's
quality due to the lack of crosstalk. Cabletron System's
10BASE-T Twisted Pair products will work on shielded
twisted pair cable with 75 to 165 ohms of impedance.
•
Jitter - Intersymbol interference and reflections can cause
jitter in the bit cell timing, which results in data errors. A
10BASE-T link segment must not generate more than 5.0 ns
of jitter. If your cable meets the impedance requirements for
a 10BASE-T link, jitter should not be a concern.
•
Delay - The maximum propagation delay of a 10BASE-T link
segment must not exceed 1000 ns. This 1000 ns maximum
delay limits the maximum link segment length to no greater
than 200 meters.
SPECIFICATIONS/REQUIREMENTS
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