GSM modem debugging
This troubleshooting page helps you find the possible
reasons of GSM modem problems. Please browse through this page
to be sure that your GSM modem operates effectively.
Steps for connecting the GSM modem to the PC
- First of all, when you start to configure your
GSM modem connectivity you need to
put the SIM card into the GSM modem. If you put the SIM card properly into
the GSM modem then the modem will blink.
- Then the GSM modem needs to be connected to the PC. If the computer has a
serial port (RS232) then the serial cable of the GSM modem can
be used for connection. If the computer does not have serial port, you will
need an USB-RS232 converter.
- If the GSM modem has been connected to the computer, check the port used
by the GSM modem in Device Manager.
Commands for Hyper Terminal
Now please start Hyper Terminal. Select the port that is used
by the GSM modem in Connect using field (You have checked the port in the
previous step). Click on OK (Figure 1).
Figure 1 - Select the port
Select the port properties in the next window (Figure 2).
Wavecom modems need 115200 Bits per second bandwidth.
Figure 2 - Port properties
Type at and press Enter in Hyper Terminal. This
at command calls the modem. OK is returned from the modem (Figure
3). If OK is not returned back or there is no response at all then
the modem does not support at commands.
Figure 3 - Call the modem
TYPE: at+cgmi and press Enter.
RESPONSE: modem manufacturer information (Figure 4).
Figure 4 - Modem manufacturer information
TYPE: at+cgmm and press Enter.
RESPONSE: list of supported frequency bands (Note: GSM 900 MHz primary band.
Other possible answers: "900E" (extended band), "1800" (DCS), "1900" (PCS) or
"MULTIBAND") (Figure 5).
Figure 5 - List of supported frequency bands
TYPE: at+cpas and press Enter (Figure 6).
RESPONSE: This command returns the activity status of the mobile equipment.
0: ready (allow commands from TA/TE)
1: unavailable (does not allow commands)
3: ringing (ringer is active)
4: call in progress
5: asleep (low functionality)
Figure 6 - Activity status of the mobile equipment
TYPE: at+cops? and press Enter (Figure 7).
RESPONSE: current operator information.
Response value: mode, format, operator
Figure 7 - Current operator information
TYPE: at+cops=? and press Enter.
RESPONSE: information about all the available operator.
Response syntax for AT+COPS=?:
+COPS: [list of supported (<stat>, long alphanumeric <oper>, short
numeric <oper>) s]
The parameters are the following ones:
0: automatic (default value)
2: deregistration ; ME will be unregistered until <mode>=0 or 1 is selected.
3: set only <format> (for read command AT+COPS?)
4: manual / automatic (<oper> shall be present), if manual selection fails,
automatic mode is entered.
<format>: format of <oper> field
0: long alphanumeric format <oper>
1: short alphanumeric format <oper>
2: numeric <oper> (default value) <stat>: status of <oper>
Operator identifier (MCC/MNC in numeric format only for operator selection)
The long alphanumeric format can be up to 16 characters long (see appendix 18.12
for operator names description, field is "Name")
The short alphanumeric format can be up to 8 characters long.
Figure 8 - Information about all the available operator
TYPE at+creg? and press Enter.
RESPONSE: information about network registration status
0: Disable network registration unsolicited result code (default)
1: Enable network registration code result code +CREG : <stat>
2: Enable network registration and location information unsolicited result
<stat>,<lac>,<ci> if there is a change of network cell.
0: not registered, ME is not currently searching for a new operator.
1: registered, home network.
2: not registered, ME currently searching for a new operator to register to.
3: registration denied.
5: registered, roaming.
Figure 9 - Network registration status
TYPE at+cpin? and press Enter.
RESPONSE: PIN code status
+CPIN: READY: it does not require PIN code or the PIN code has been
Figure 10 - PIN code status
Sending SMS from Hyper Terminal
To send test SMS messages from Hyper Terminal please type the
following parameters in (Figure 11):
TYPE: at and press Enter.
TYPE: at+cmgs="recipient phone number" press Enter (For example:
RESPONSE: >. Please type the message you wish to send out. (For example:
> test message from Hyper Terminal)
Now press CTRL + Z
Response: +CMGS: 83 that is a confirmation and OK.
After you entered these parameters the message will be sent out.
Please note that SMS messages will be sent in Text mode instead of
Figure 11 - Parameters for sending SMS from Hyper Terminal
AT Commands Interface Guide
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