Cabletron Systems SEHI SEHI100TX- User Manual

Also see for SEHI100TX-22: User guide User guide

Contents

Chapter 3: Installation Requirements and Specifications3-2SEHI100TX User’s Guide3.1.2 UTP Cable SpecificationsThe device at the other end of the twisted pair segment must meet IEEE802.3u 100BASE-T specifications. When connecting a 100BASE-TXTwisted Pair Segment to the SEHI twisted pair network ports and theEPIM-100TX module, the network must meet the followingrequirements:LengthThe IEEE 802.3u 100BASE-T standard requires that 100BASE-TXdevices be capable of transmitting over a 100 meter (328 foot) link usingCategory 5 UTP wire.ImpedanceUTP cables typically have an impedance of between 85 to 110 ohms.JitterIntersymbol interference and reflections cause jitter in the bit cell timing,resulting in data errors. A 100BASE-TX link must not generate more than1.4 ns of jitter. If the cable meets the impedance requirements for a100BASE-TX link, jitter should not be a concern.CrosstalkCrosstalk is caused by signal coupling between the different cable pairscontained within a multi-pair cable bundle. 100BASE-TX transceivers aredesigned so that the user does not need to be concerned about cablecrosstalk, provided the cable meets all other requirements.NoiseNoise is caused by either crosstalk or externally induced impulses.Impulse noise may cause data errors if the impulses occur at very specifictimes during data transmission. Generally, the user need not be concernedabout noise. If noise-related data errors are suspected, it may be necessaryto either reroute the cable or eliminate the source of the impulse noise.