Cabletron Systems SEHI-22FL Mode D'Emploi

Chapter 3: Installation Requirements and Specifications

Crosstalk is caused by signal coupling between the different cable pairs 
contained within a multi-pair cable bundle. 10BASE-T transceivers are 
designed so that the user does not need to be concerned about cable 
crosstalk, provided the cable meets all other requirements.

Noise is caused by either crosstalk or externally induced impulses. 
Impulse noise may cause data errors if the impulses occur at very specific 
times during data transmission. Generally, the user need not be concerned 
about noise. If noise-related data errors are suspected, it may be necessary 
to either reroute the cable or eliminate the source of the impulse noise.

Multi-pair PVC 24 AWG cables typically have an attenuation of
8 dB to 10 dB/100 meters at 20

°

C (68

°

F). The attenuation of PVC 

insulated cable varies significantly with temperature. At temperatures 
greater than 40

°

C (104

°

F), Cabletron Systems recommends the use of 

plenum-rated cables to ensure that cable attenuation remains within 
specification.

The SEHI-22FL provides ST-type ports for 10BASE-FL Multimode Fiber 
Optic cabling. Figure 3-1 shows the network ports.

7

8

9

10

11

12

1

2

3

4

5

6

09162_04

SEHI Book  Page 4  Friday, April 19, 1996  10:46 AM