Chapter 4 – Troubleshooting and Frequently Asked Questions
Multi-Tech Systems, Inc. MultiModem GPRS USB Wireless Modem User Guide
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Frequently Asked Questions
Which providers can I use?
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Two major providers are T-Mobile and Cingular.
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We are Cingular approved.
Does this modem support High-Speed Circuit-Switched Data (HSCSD)?
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No, our GSM/GPRS modems do not support HSCSD.
The modem is answering, but seems to not be doing anything?
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The modem is answering in voice mode.
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If you are trying to make a data call, make sure the account has CSD service. You will also need the data
number (separate number from the main phone number that is provided by the provider).
I am trying to make a data connection by dialing from my wireless modem to an analog modem. Why does
the analog modem answer and send tones, but never connect?
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To make a data call you must use the ATD<number> command.
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Make sure the account has CSD service.
How do I get the voice portion to work so I can talk to others using the wireless modem?
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You will need a cable that has the speaker pins connected to a speaker and microphone.
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We have a “Y” cable that splits out to a RJ9 connector that can be used to plug into the receiver of a
handset.
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‘ATD<number>;’ will originate a voice call.
How do I make an Internet connection to my dial-up ISP?
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Make sure you have CSD service.
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Create a dial-up connection to the ISP’s access number, then use your account username and password
and choose the wireless modem as the device.
How does faxing work?
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GPRS modems support Class 1 and Class 2 Group 3 faxing.
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You will need fax services setup on your account. You should receive a separate phone number for fax just
like voice and data, and you must call the fax number for the modem to receive a fax.
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You will also need fax software (we do not have working software). WinFax Version 10 has been tested with
success.
I can’t make outgoing calls. I just receive a NO CARRIER response.
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Make sure the antenna is connected and SIM is inserted correctly.
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Check signal and registration: ‘AT+CSQ’ (10-31 is good), ‘AT+CREG?’ (0,1 is registered & 0,5 is roaming).
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Check NO CARRIER reason with ‘AT+CEER’. Look up error code in Reference Guide.
The modem will not answer.
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To have modem autoanswer, set modem with ‘ATS0=1’ and ‘AT&W’ to store the setting.
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Send ‘ATA’ to the modem once the RING is indicated on the terminal screen.
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You may need to set modem to ignore DTR, ‘AT&D0’, if you aren’t providing DTR.
I am trying to make a GPRS connection using a Windows dial-up session. It connects and then immediately
disconnects.
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Make sure the APN is configured in the modem correctly (The APN is provided by the provider).
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Check the APN with ‘AT+CGDCONT?’ To make sure it is correct.
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If no APN is inserted, then insert the correct APN using the command ‘AT+CGDCONT=1,”IP”,”<APN>”’ with
HyperTerminal or add it into the “Extra Initialization Commands:” in the modem’s properties.
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Make sure the APN is correct for your account.
When I try to establish a GPRS connection using Windows dial-up I get an error: “Hardware Failure”.
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Check the modem to make sure it is installed and can be queried in the modem’s properties.
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Make sure the com port 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.
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Make sure the dial-up connections maximum speed matches the modem’s properties maximum port speed.
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Try rebooting the PC.
What is the maximum amount of characters I can use to send an SMS message?
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Supports up to 160 characters maximum.
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In PDU mode using 7-bit, the modem still supports 160 characters, but in 8-bit the modem will support only
70 characters.
