Enterasys Networks 2H252-25R ユーザーズマニュアル

3. Verify that a link exists by checking that the port RX LED is on (flashing amber, blinking green, 

or solid green). If the RX LED is off and the TX LED is not blinking amber, perform the 
following steps until it is on:

a. Verify that the LED switch located near the COM port of the device is in the left-most 

position (RX and TX LED indicators).

b. Verify that the UTP cabling used is Category 3 (for 10BASE-T) or Category 5 (for 

10BASE-T or 100BASE-TX). The Category 5 cabling must have an impedance of between 
85 and 111 ohms.

c. Verify that the 100BASE-TX device at the other end of the twisted pair segment is powered 

up.

d. Verify that the RJ45 connector on the twisted pair segment has the proper pinouts. 

Depending on what device is connected to the 2H252-25R, a straight-through or crossover 
cable may be used. 

 shows the wiring for both types of cables.

e. Check the cable for continuity.

NOTE: If a port is to operate at 10 and 100 Mbps, Category 5 cabling must be used. 
Refer to 

 for information about 100BASE-TX networks and cabling.

Receive (RX)

Transmit (TX)

4005_00_07

Twisted Pair Cable

Port

LED MODE Switch

in RX–TX position

LED MODE Switch