IBM 5500 Operational, Installation, And Maintenance Manual page 80

80
• The host modem answers the phone
- Leased Lines
At this time, leased lines cannot be directly connected to the 5500
Control Unit. Until this support is available, you can place a router
between the leased line and the 5500 Control Unit.
ISDN
• What kind of interface do you have?
"S/T" interfaces require an external termination (NT-1). "U" interfaces do
not require this termination.
Modem
• Is the modem powered?
In many cases, recycling the modem (turning off power and turning it
back on) will resolve many problems. If the modem is hung, it may be
necessary to shutdown the 5500 Control Unit and recycle the modem
while the 5500 is sounding the beeps for "shutdown complete". Starting
the 5500 Control Unit with the modem powered on may correct the
problem.
• What type of modem is being used? Only Asynchronous or ISDN
modems are supported. Synchronous modems will not work on the 5500
Communication Lines.
• Are all physical switches on the modem set correctly? Check the
instructions from the manufacturer.
• ISDN modems must be pre-configured before attachment to the 5500
Control Unit. Consult the manufacturer's documentation correctly set the
following:
- Interface Type
- Service Profile IDs (SPIDs)
- Directory Numbers (DNs)
- Terminal Endpoint Identifiers (TEIs)
- Connection Type
• For Switched Lines, does the modem's speaker indicate the following:
- Dial Tone is present
- Number is being dialed
- Phone is being answered at the host
- Connect tones indicate the modems are attempting to negotiate a speed
• Check the modem lights that indicate communication with the 5500
Control Unit
- OH (Off Hook) for Asynchronous Modems indicates that the 5500
Control Unit is attempting to contact the host modem
- Channel-In-Use on ISDN modems has a similar meaning as OH.
- SD/RD (Send Data, Receive Data) indicates that data is being
transferred between the modem and the 5500 Control Unit.
Planning, Installation, and Maintenance Guide
Chapter 5: Troubleshooting