Cabletron Systems EMC39-12 用户手册
EMC39-12 User’s Guide
Page A-1
APPENDIX A
CABLE REQUIREMENTS
This appendix provides cable requirements for each of the EMC39-12
ports.
ports.
A.1 10BASE-T TWISTED PAIR REQUIREMENTS
When you connect a 10BASE-T twisted pair segment to the EMC39-12,
the device at the other end of the twisted pair segment must meet IEEE
802.3 10BASE-T specifications. Your 10BASE-T twisted pair segment
must meet the following requirements.
the device at the other end of the twisted pair segment must meet IEEE
802.3 10BASE-T specifications. Your 10BASE-T twisted pair segment
must meet the following requirements.
Segment Length
The IEEE 802.3 10BASE-T standard requires that 10BASE-T devices
must be able to transmit from 0 to at least 100 meters (328 feet) per
segment of 24-gauge unshielded twisted pair (UTP) cable.
must be able to transmit from 0 to at least 100 meters (328 feet) per
segment of 24-gauge unshielded twisted pair (UTP) cable.
Insertion Loss
The maximum insertion loss allowed for a 10BASE-T segment is 11.5 db
at all frequencies between 5.0 and 10.0 MHz. This includes the
attenuation of the cable, connectors, and patch panel.
at all frequencies between 5.0 and 10.0 MHz. This includes the
attenuation of the cable, connectors, and patch panel.
Impedance
10BASE-T specifies cable impedance between 85 and 110 ohms.
A.2 SINGLE MODE FIBER OPTIC NETWORK
When connecting a single mode fiber optic link segment to a hub, ensure
the network meets the following requirements:
the network meets the following requirements:
Cable Type
Fiber optic link segments should consist of 8/125 to 12/125
µ
m single
mode fiber optic cabling. You can also use 62.5/125
µ
m multimode cable
however, multimode cable allows for greater optical loss, and limits the
possible distance to 2 km.
possible distance to 2 km.
emc39bk Page 1 Monday, February 12, 1996 4:21 PM