No Connection - IBM 5500 Operational, Installation, And Maintenance Manual

No Connection

A connection with your host cannot be established. This symptom could
indicate a problem with the physical (hardware) connections, or with the
configuration of the WAN components. The 5500 Control Unit attempts to
connect to the host every 30 seconds. When observing these connection
attempts at a modem, you should wait up to 30 seconds before determining
the next step.
If the WAN connection has previously operated successfully, a simple
shutdown and restart of the 5500 Control Unit could solve the problem. Refer
to Step 6 on page 52 and "Shutting Down" on page 65.
If a simple shutdown does not solve this problem, or if this is the initial
installation, check and follow the suggestions listed in "Physical Connection
Problems" on page 79. If your problem continues, then follow the suggestions
listed in "Configuration Problems" on page 81.
Physical Connection Problems
Check the following list of physical connections:
Modem Cable
• Is this the correct cable specified by the modem manufacturer?
The 5500 Control Unit is a DTE (Data Terminal Equipment) and modems
are usually a DCE (Data Circuit-terminating Equipment). Therefore, use a
straight-through cable rather than a null-modem cable.
Inexpensive serial cables may not contain all the signal lines required by
the modem.
The signal ground of the Communication Line is connected to the 5500
Control Unit's frame ground. Therefore, the signal ground should not be
connected to the frame ground in the modem. This could be caused by a
cable problem.
• Is the cable connected to the modem properly?
• Is the cable connected to the correct port on the 5500 Control Unit?
The connector labeled "Communication Line 0" corresponds to WAN 0,
and "Communication Line 1" corresponds to WAN 1.
Phone Line
• Are you using an analog phone line? Most modems do not operate with a
digital phone system.
• Is the phone line connected to the modem?
• What type of line is being used?
- Switched Line
Is the line operational? Use a handset to verify the following:
• A dial tone can be heard
• The host phone is not busy
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