Multi-Tech Systems MTA128NT 用户手册

This chapter describes basic problems you may run into with your MTA128ST/NT and how to solve them.
Your MTA128ST/NT 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, it is possible that the
MTA128ST/NT is defective. However, it is more likely that the source of your problem lies elsewhere.
Problems you may encounter include the following:

• None of the LEDs light when the MTA128ST/NT is on.

• The MTA128ST/NT does not respond to commands.

• The MTA128ST/NT 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/NT disconnects while online.

• The MTA128ST/NT 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 7).

SITUATION 1: The 

!Hn and *!Hn commands can be very useful for certain RAS environments that require

at least 1 second to initialize a port after a call has disconnected (such as Citrix and Novell). For example,
when a call disconnects, Citrix and Novell will begin initializing the port that just disconnected. However, it
typically takes more than 1 second and during that time a call may be received by the digital or analog
port. When this happens, Citrix and Novell do not answer the call nor do they finish the initialization
process. To prevent this problem, setting 

!H5 and/or *!H5 will set the TA to hold of digital and/or analog

calls for 5 seconds after the respective port(s) disconnect(s). This should give enough time for the digital
and/or analog port to be initialized by Citrix or Novell and enter the “waiting for a call” state.

SITUATION 2: The autobauding code cannot differentiate between 7 data bits, no parity, 1 or 2 stop bits
(7N1 or 7N2) and 7 data bits, mark parity, 1 or 2 stop bits (7M1 or 7M2). The TA assumes 7 data bits, mark
parity, 1 stop bit (7M1) and this case covers 7N1, 7N2, 7M1 and 7M2. However, if for some reason the
assumption of 7M1 causes a problem, then there is a workaround. The addition of the 

%S3 command and

use of 

$SBn, @P3=n, @P4=n, and @P6=n will help work around this limitation. See the description for the

%Sn command.

SITUATION 3: The autobauding code cannot differentiate between 8 data bits, no parity, 1 or 2 stop bits
(8N1 or 8N2) and 7 data bits, space parity, 1 or 2 stop bits (7S1 or 7S2). The TA assumes 8 data bits, no
parity, 1 stop bit (8N1) and this setting covers 7S1, 7S2, 8N1 and 8N2. However, if for some reason the
assumption of 8N1 causes a problem, then there is a workaround. The addition of the 

%S3 command and

use of 

$SBn, @P3=n, @P4=n, and @P6=n will help work around this limitation. See the description for the

%Sn command.