Multi-Tech MultiModem ISIHI-2S, Manual

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MultiModemISI Hybrid Series, ISIHI-2S 115
Chapter 6—Troubleshooting Guide
The Terminal Adapter Disconnects While Online
• Check for loose connections between the computer, the ISDN jack, and AC power.
• The problem may have originated at the other end of the line. Try again.
• If you were online with a BBS or online service, it may have hung up due to lack of
activity on your part or because you exceeded your time limit for the day. Try again.
The Terminal Adapter Cannot Connect When Answering
• Autoanswer may be disabled. Turn on autoanswer in your data communications
program, or send the command ATS0=1 to your TA in terminal mode.
Note: If you want to accept calls while DTR is low, the TA must be configured to ignore
DTR. This is accomplished by entering AT&D0<cr>. With this configuration, the TA is able
to accept calls while DTR is low. If this configuration setting is not made, the TA rejects
incoming calls until DTR is high while the calls comes in.
File Transfer Appears Slower Than It Should Be
• If you presently have a Universal Asynchronous Receiver/Transmitter (UART) that is
compromising data throughputs, we recommend you replace it with a special I/O card.
• If you are running under Windows 3.1 and have a 16550AFN UART, you must replace
the Windows serial driver, COMM.DRV, to take full advantage of the UART’s speed.
• Check the serial port baud rate in your communications software and make sure it is
set as high as your UART allows.
Data Is Being Lost
• Your UART may not be reliable at serial port speeds over 9600 bps or 19,200 bps.
Reset your serial port speed to a lower rate or replace your serial port with a faster one.
• Check the serial port baud rate in your communications software, and make sure it is
set as high as your UART allows.
• Make sure the flow control method you selected in software matches the method
selected in the TA.
There Are Garbage Characters on the Monitor
• Your computer and the remote computer may be set to different parities. Check with
the remote system with which you are communicating and set your communications
software to use the same parity as the remote system.