Multi-Tech Systems MTCBA-G-U-F4 Troubleshooting Examples, Situation a The modem does not answer

Chapter 4 – Troubleshooting and Frequently Asked Questions

Chapter 4 – Troubleshooting and

Frequently Asked Questions

Troubleshooting Examples

Before calling the Multi-Tech Technical Support, check to the following connections:

•The right antenna is connected to the modem

•The serial cable connection is correct

•The power is connected correctly and the power lights on the modem are on

•Verify your signal strength

•Verify your network registration

•Use the following situation examples to troubleshoot the modem not answering and the modem returning a No Carrier message.

Situation A: The modem does not answer

If the Wireless MultiModem does not answer through the serial link upon an attempted transmission of data or voice signals, see the table below for possible causes and solutions.

Solutions for ‘no connection through serial link’ situation

If the	Then ask …	Action
modem
returns …
(nothing)	Is the communication program	In communications program, verify that modem
	properly configured?	parameters have been set to the values shown here:
		Data bits = 8
		Parity = none
		Stop Bits = 1
		Baud = 115200 bps
	Is another program interfering	Close any such application program.
	with the communication
	program?
	Is the modem set to	Type ATS0=1 (to set to auto answer on the first ring)
	autoanswer?	Type ATA (to set to manual answer)
	Is the communication program	Type ATS0=1 (to set to auto answer on the first ring)
	receiving RING responses?	Type ATA (to set to manual answer)

Situation B: The modem always returns «No carrier» when trying to originate a call

Solutions for “no carrier” message

If the modem	Then ask …	Action
returns …
no carrier	Is the selected bearer type	Type AT+CEER to view the extended error code (see
(esp. for data	supported by the called	“Error Results Codes" in the AT Command guide).
communication)	party?	Be sure that the selected bearer type is supported by the
		called party.
	Is the selected bearer type	Be sure that the selected bearer type is supported by the
	supported by the network?	network.
		If no success, try bearer selection type: AT+CBST=0,0,3
		Be sure SIM card is available for data/fax calls.
no carrier		Be sure that the semicolon character (“;”) is typed
(esp. for voice		immediately after the phone number in the AT command;
communication)		e.g., ATD######;

Multi-Tech Systems, Inc. MultiModem GPRS USB Wireless Modem User Guide 31