Chapter 3 – Troubleshooting
Multi-Tech Systems, Inc. MultiModem® GPRS with USB User Guide 34
The modem will not answer.
• To have modem auto-answer, set modem with ‘ATS0=1’. Use ‘AT&W’ to store the setting.
• Send ‘ATA’ to the modem once the RING is indicated on the terminal screen.
• If you aren’t providing DTR, you may need to set the modem to ignore DTR by using this command:
‘AT&D0’ .
Which providers can I use?
• T-Mobile, AT&T, and Cingular
• AT&T doesn’t support CSD (wireless to analog connection)
I am trying to make a GPRS connection using a Windows dial-up session. It connects and then
immediately disconnects. What’s wrong?
• Make sure the APN is stored in the modem (the APN is given by the provider).
• Check the APN with ‘AT+CGDCONT?’ to make sure it is correct.
• If no APN is inserted, then insert the correct APN: ‘AT+CGDCONT=1,”IP”,”<APN>”’.
When I try to make a GPRS connection using Windows dial-up I get this error: “Hardware Failure”.
• Check the modem to make sure it is installed. Check the Modem Properties screen to be sure the
modem can be queried.
• Make sure the modem is not being held by another application. Look for the TR light indication. If it is
on, most likely another application is holding onto the port.
• Try rebooting the system.
What is the maximum number of characters I can use to send a SMS message?
• The modem supports up to 160 characters max.
• In PDU mode using 7-bit, the modem still supports 160 characters. But in 8-bit mode the modem will
only support 70 characters.