Specifications

112 MultiModemISI Hybrid Series, ISIHI-2S/2U
Chapter 6—Troubleshooting Guide
Troubleshooting
This chapter covers common problems you may have with your ISIHI-2S/2U and how to
solve them. The ISIHI-2S/2U was thoroughly tested at the factory before shipping. If you
are unable to connect successfully, or if you experience data loss or garbled characters,
during connecting, it is possible the modem or terminal adapter is defective. However, it
is more likely that the source of your problem lies elsewhere. Always make sure all
hardware is connected properly. Then review the common problems listed in this chapter
for recommendations on what to change or do. Problems you may encounter include the
following:
 The TA/modem does not respond to commands.
 The TA/modem dials but cannot make a connection.
 You can place data calls but not voice calls, or vice versa.
 You cannot place two simultaneous data calls.
 The TA/modem disconnects while online.
 The TA/modem cannot connect when answering.
 File transfer appears slower than it should be.
 Data is being lost
 There are garbage characters on the monitor
If you experience problems, please check the following possibilities before calling Tech
Support (see Chapter 6).
The terminal adapter does not respond to commands
 Make sure you issue commands from the data communications software, either
automatically or manually, in terminal mode. (You cannot send commands to the TA/
modem from the DOS prompt.)
 Make sure you are in terminal mode in your data communications program; then type
AT and press ENTER. If you get an OK response, your connections are good and the
problem likely is in your phonebook entry or session settings.
 If you dont get an OK, the problem may still be in the communications software. Make
sure you have done whatever is necessary in your software to make a port connection.
Not all communications programs connect to the COM port automatically. Some
connect when the software loads and remain connected until the program ends. Others,
like MultiExpress Terminal, can disconnect without ending the program (make sure the
Connect icon looks plugged in). MultiExpress Terminal also allows multiple terminals
to be open, but only one can access the modem/TA at a time.
 Your communications software settings may not match the physical port where the TA
is connected. The serial cable may be plugged into the wrong connectorcheck your
computer documentation to make sure. Or, you may have selected a COM port in your
software other than the one where the TA/modem is connectedcompare the settings in
your software to the connection.