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APPENDIX A
EPIM SPECIFICATIONS
The Ethernet Port Interface Module slides into the front of the
ETWMIM and allows access to Ethernet. This module is only used if
the FNB Ethernet connection is not in use. See Section 3.3 for
information on selecting the Ethernet connection.
A.1 EPIM CABLING GUIDELINES
The following sections describe network design guidelines for
connecting the ETWMIM front panel EPIM to the network.
A.1.1 Twisted Pair Cable Requirements for the EPIM-T
The device at the other end of the twisted pair segment must meet
IEEE 802.3 10BASE-T specifications. When you connect a 10BASE-T
Twisted Pair Segment to the EPIM-T module, your network must
meet the following requirements:
Length
The IEEE 802.3 10BASE-T standard requires that 10BASE-T devices
transmit over a 100 meter (328 foot) link using 22-24 AWG unshielded
twisted pair wire. However, cable quality largely determines
maximum link length. If you use high quality, low attenuation cable,
you can achieve link lengths of up to 200 meters. Cable delay limits
maximum link length to 200 meters, regardless of the 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 link segment.
Impedance
Cabletron Systems 10BASE-T Twisted Pair products will work on
twisted pair cable with 75 to 165 ohms impedance. Unshielded twisted
pair cables typically have an impedance of between 85 to 110 ohms.
You can also use shielded twisted pair cables, such as IBM Type 1
cable, but keep in mind that this cable has an impedance of 150 ohms.
Page A-1
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