Multi Tech Equipment GPRS USB - Manual (Page 29)

Chapter 4 – Troubleshooting and Frequently Asked Questions
Multi-Tech Systems, Inc. MultiModem GPRS USB Wireless Modem User Guide 29
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
modem
returns … Then ask … Action
Is the communication program
properly configured? In communications program, verify that modem
parameters have been set to the values shown here:
Data bits = 8
Parity = none
Stop Bits = 1
Baud = 115200 bps
Is another program interfering
with the communication
program? Close any such application program.
Is the modem set to
autoanswer? Type ATS0=1 (to set to auto answer on the first ring)
Type ATA (to set to manual answer)
(nothing)
Is the communication program
receiving RING responses? Type ATS0=1 (to set to auto answer on the first ring)
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
returns … Then ask … Action
no carrier
(esp. for data
communication) Is the selected bearer type
supported by the called
party?
Is the selected bearer type
supported by the network? Type AT+CEER to view the extended error code (see
“Error Results Codes" in the AT Command guide).
Be sure that the selected bearer type is supported by the
called party.
Be sure that the selected bearer type is supported by the
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
(esp. for voice
communication) Be sure that the semicolon character (“;”) is typed
immediately after the phone number in the AT command;
e.g., ATD######;