64
C
HAPTER
5: D
IAGNOSTICS
AND
T
ROUBLESHOOTING
Figure 20
Internal Packet Test Window
Running the External Loopback Test
The external loopback test checks the integrity of the
on-board transceiver and cable connectors.
To run the external loopback test, you must use a
loopback plug.
CAUTION:
Do not run the External Loopback Test when
the 3C985B-SX server NIC is cabled to another device.
To run the external loopback test:
1 Insert the loopback plug into the 3C985B-SX
server NIC.
For instructions on constructing a loopback plug, see
Constructing Loopback Plugs
in this chapter.
2 Bring up the Packet Test window (
Figure 19
):
a
Start the 3Com NIC Diagnostics program.
b
Click the Diagnostics tab.
c
Click
Choose
Test
.
3 In the External Loopback Test area, click
Start
.
The External Packet Test window appears (
Figure 21
).
Book Page 64 Monday, June 7, 1999 2:14 PM
