Siemens DataNET Hub (DNH) - Manual (Page 75)

2000585-001 Data Communications Setup •••• 67
Troubleshooting, Continued
If a DNH port green LED is off, or intermittently flashes between green
and red the signal levels for that port are either too high or low relative to
the other Hub ports.
If a port link fails to connect at all, the port can be set to a test mode The
test mode will cause port activity to occur approximately every 50 milli-
seconds instead of approximately every 7 seconds as it would for an un-
connected link. While in the test mode the signal for that port can be
measured.
1. Connect a standard 9-pin COM cable from the designated PC COM
port (see page 49, step 7.) to the Configuration Port on the hub half
containing the port in question.
2. Open HyperTerminal program on your PC; reference Configuring
Your PC, page 49.
3. Connect and Log on to the DNH.
4. At the >>>> prompt type: port stop num
Where num is a port number 1 through 9
5. Press ↵ ↵↵ ↵ Enter.
6. At the >>>> prompt type: test num
This places the selected port into a hardware diagnostic mode.
7. Using Option 1 or 2, (as outlined in ‘Hub Signal Equalizer Board with
Generic Cable’ section page 37) connect an oscilloscope to the port
under test.
8. The signal received at the slave should be between ~0.75 v p-p and
5 v p-p.
9. If the signal is smaller than ~0.75 v p-p adjust the impedance match-
ing jumpers to increase the signal level.
10. At the >>>> prompt type: port start num
Where num is a port number 1 through 9.
11. Press ↵ ↵↵ ↵ Enter.
Signal Quality
Problems
Instructions