Multi-Tech Systems MTA128NT - Manual (Page 38)

Troubleshooting
MTA128ST/NT 38
• If the MTA128ST/NT reports NO DIALTONE, check that the ISDN S/T cable is securely connected to
both the TA’s ISDN jack (not the PHONE jack) and the ISDN network terminator or wall jack. If the cable
looks secure, try replacing it. If that doesn’t work, the problem may be in your building’s telephone
installation. Make sure ISDN cables on all devices are wired straight-through (pin 1 to pin 1, pin 2 to pin
2, etc.) and do not have reversed pairs. The cable must have at least the middle four pins (pins 3, 4, 5,
and 6) connected. A reversed pair on the U (phone company) side is not important, but a reversed pair
on the S/T (your) side can create problems if you have more than one device, since multiple devices
attached to the S/T interface must all have the same polarity.
• If the MTA128ST/NT reports BUSY, the other number may be busy, in which case you should try again
later.
• If the MTA128ST/NT reports NO CARRIER, no connection was made. You might have dialed the correct
number but the other computer or software was turned off or faulty. Check the number and try again, or
try calling another system to make sure your TA is working. Also, check that you accurately configured
the TA with the correct switch type, TEIs, data protocols, and other parameters needed for a successful
call (see Chapter 3).
You can place data calls but not voice calls or vice versa
• You might not have ordered both voice and data service from your ISDN provider. Check your contract or
latest statement of service from your ISDN provider.
• Your ISDN provider may have programmed the switch incorrectly. Call the provider.
You cannot place two simultaneous data calls
• You may not have ordered an ISDN line configuration that supports two simultaneous calls. Check your
contract or latest statement of service from your ISDN provider. Also, your ISDN provider may have
programmed the switch incorrectly. Call the provider.
• You may have misconfigured your MTA128ST/NT to dial two simultaneous data calls. The command
AT&J1&W0<cr> is used to indicate whether outgoing calls should be made on two B-channels by default.
• You may be using the wrong bundling dial modifier (e.g., ATD7853500&7853502<cr>). The ampersand in
this command string is correct. Other valid characters joining two telephone numbers include a plus sign
(+) and an exclamation mark (!).
Note: In Windows 98/NT/ME, if the Use Country Code and Area Code box is checked in the Properties
window for dial-up connection, the bundling modifier (i.e., &, + or !) is removed from the dialing string
when the user attempts to make a connection. The solution is not to check the
Use Country Code and
Area Code box or to simply add the bundling dial modifier to the phone number at the time of connection.
The MTA128ST/NT disconnects while online
• Check for loose connections between the MTA128ST/NT and 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 on you because of lack of activity on
your part or because you exceeded your time limit for the day. Try again.
The MTA128ST/NT cannot connect when answering
• Autoanswer may be disabled. Turn on autoanswer in your data communications program or send the
command ATS0=1 to your MTA128ST/NT in terminal mode.
Note: If the user wishes to accept calls while DTR is low, the MTA128ST/NT must be configured to
ignore DTR. This is accomplished by entering AT&D0<cr>. With this configuration, the MTA128ST/NT 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.