Motorola 326X V.34, and V.32bis, V.34-SDC manual Flow control

Troubleshooting

326X Series Modem Troubleshooting Guide (Continued)

Problem	Diagnosis/Test	Possible Solution
Data is garbled or lost Check the modem’s flow control		• Ensure that the DTE's flow control is the same as the
	settings.	modem setting
		(for example, XON-XOFF, RTS/CTS).
		• If your communications package’s file transfer pro-
		tocol is used, and the package supports RTS/CTS
		Flow control, set Flow=RTS/CTS (AT*FL3). If the
		package does not support RTS/CTS flow control, set
		Flow=Off (AT*FL0).
	Check that the modem’s DTE	If they do not match, adjust as necessary.
	rate, parity, and character length
	match the DTE’s settings.
	If in normal mode, check line
	quality:
	• Check CQMS parameters
	(signal quality and error
	probability).
	• Run a remote digital	If no errors occur, the line is good.
	loopback (RDL) or RDL	If errors occur, perform a manual retrain, or retry the
	with pattern test.
		phone call.
	• If you are still receiving	If the LAL or LAL with pattern test fails, contact Motor-
	errors, disconnect the	ola Customer Support.
	modem from the line and	If the LAL or LAL with pattern test passes, you may have
	perform a local analog
		a line problem (contact your telephone company) or a
	loopback (LAL) or LAL
		problem with your application (check with your software
	with pattern test (with
		vendor).
	modem flow control off).
Data stops passing	Modem could be in “flow off”	• Set the modem for hardware flow control.
	condition (modem set for XON-	• Set Flow=Off (AT*FL0).
	XOFF and DTE set for hardware

flow control).

The modem connects at a lower rate than the maximum (as set in the Max Rate (AT*MX) option)

Check CQMS parameters for line quality.

Ensure that the remote modem supports the DCE rates you anticipate.

Line quality is not sufficient to support higher data rate. If line quality improves, the modem will increase its speed automatically.

Excessive modem	Retry call.	Continuous retrains indicate a line problem. Contact your
retrains		telephone company.

6-6 Troubleshooting Guide