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Troubleshooting Guide 6-7
Troubleshooting
CALL
TERMINATION
Modem takes too long to
disconnect
Check to see if remote modem
supports PSTN cleardown.
If remote modem doesn't support PSTN cleardown, try to
change the setting of DCD Loss Disconnect (AT
*
CD)
to a smaller number.
Modem doesn't
disconnect when DTR
drops, or
Modem doesn’t
disconnect when
communications
software package does
Check modem’s DTR option for
correct setting.
• Set DTR to an option other than High.
• Set DTR=Discon (AT&D2).
Communications
software package won't
signal the modem to
return to command state
when escape sequence
(+++) is issued
Check the delay between issuing
the escape sequence (+++) and
the ATH command.
Ensure the escape sequence (+++) complies with the
modem’s guard time requirements (refer to Line feed
character:S-Register 4 for details).
Check whether the modem is set
for AT ACU.
Set ACU Select=AT (ACU OPT's menu).
FILE TRANSFER
Can't transfer all of a
file or a file aborts in
the middle of transfer
Check the modem’s flow control
settings.
Ensure that the DTE's flow control is the same as the
modem’s setting (for example XON-XOFF, RTS/CTS).
Check whether your
communications package
supports speed conversion.
If your communications software supports speed
conversion, set modem’s Speed Conver=On (AT
*
SC1).
It takes longer than
expected to transfer a
file
Confirm which file transfer
protocol you are using.
Use different protocol, for example, YMODEM,
Y-GMODEM.
If operating the 326X-SDC modem in SDC mode, and you experience this type of problem...
BER tests do not work
BER tests do not work in SDC
mode because data is not framed.
Modem won’t pass data
Ensure your DTE protocol is
HDLC/SDLC-like data.
If your protocol is not HDLC/SDLC-like, use direct
mode.
Check for data format mismatch
between modem and DTE
(AT
*
DF).
Set data format option to match the DTE [NRZ
(AT
*
DF0) or NRZI (AT
*
DF1)].
Check clocking requirements. Set modem for internal or external clock as required by
your application.
326X Series Modem Troubleshooting Guide (Continued)
Problem Diagnosis/Test Possible Solution