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MultiModemISDN User Guide
Introduction
This chapter describes basic problems you may run into with your MTA128ST-USB and how to solve
them. Your MTA128ST-USB was thoroughly tested at the factory before it was shipped. If you are
unable to make a successful connection, or if you experience data loss during your connection, check
the following possibilities before calling Technical Support (see Chapter 6).
• None of the LEDs light when the MTA128ST-USB is on.
• The MTA128ST-USB does not respond to commands.
• The MTA128ST-USB 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 MTA128ST-USB disconnects while online.
• The MTA128ST-USB cannot connect when answering.
• File transfer appears slower than it should be.
• Data is being lost.
• There are garbage characters on the monitor.
None of the LEDs light when the MTA128ST-USB is on
When you turn on the MTA128ST-USB, the LED indicators on the front panel should flash briefly as
the unit runs a self-test. If the LEDs remain off, the unit probably is not receiving power.
• Make sure the MTA128ST-USB’s power switch is on, especially if you normally turn on the unit
by turning on a power strip.
• If the power supply is plugged into a power strip, make sure the power strip is plugged in and
its power switch is on.
• Make sure the power supply module is firmly connected to the MTA128ST-USB and to the
wall outlet or power strip.
• If the power strip is on and the MTA128ST-USB is switched on, try moving the unit’s power
supply to another outlet on the power strip.
• Test that the outlet is live by plugging another electrical device into it.
• The MTA128ST-USB or power supply may be defective. If you have another Multi-Tech
MTA128ST-USB, try swapping units. If the problem goes away, the first unit or power supply
may be defective. Call Tech Support for assistance.
Caution: Do not under any circumstances replace the power supply module with one designed for
another product, as it may damage the MTA128ST-USB and void your warranty.
The MTA128ST-USB does not respond to commands
• Make sure the MTA128ST-USB is plugged in and turned on. (See
None of the LEDs Light
When the MTA128ST-USB Is On.
)
• Try resetting your MTA128ST-USB by turning it off and on.
• Make sure you are issuing the MTA128ST-USB commands from the data communications
software, either automatically, or manually in terminal mode. (You cannot send commands to
