Test GSM modem operation

[Sergio Bertana]

To test the operation of a GSM MODEM (BGS2 or GT863) must be connected to the serial line of the PC using a modem cable (Example ns Cbl058 * 300) and a terminal emulation software (Example Toolly) set with the typical communication parameters "9600, n, 8,1". From the terminal it will be possible to send commands to the modem and read the response strings. Below is a reference to a documentation.

[Sergio Bertana]

Meaning flashes Modem status LED TC35i and MC35i.
The green status LED indicates with its condition the different states in which the modem is located.

Turned off: The modem is switched off or in SLEEP mode.
Flashing 600 ms On / 600 ms Off: The SIM card is not inserted, the PIN code has not been entered, the modem is connecting to the network.
Flashing 75 ms On / 3 Sec Off: The modem is connected to the network.
75 blinking ms on / 75 ms Off / 75 ms On / 3 s Off: Report GPRS packages in transit.
Access: Modem connected with remote device, data communication or voice in progress.

[Sergio Bertana]

Reading the SIM card identification number. Connect the modem to the serial line of the PC using a modem cable and a terminal emulation software set with the typical communication parameters “9600, n, 8,1”.
 
From the terminal send the AT command to read SIM card ID: AT^SCID followed by the return.
The modem responds with the message: ^SCID: <cid> OK

[Authorless]

I have a Cinterion TC35I modem and by connecting it to a terminal emulation program I am trying to send and receive SMS but while the sending procedure works correctly, I cannot read the SMS received.

You can give me some information about this.

[Sergio Bertana]

Connect the modem to a terminal emulation program (Hyperterminal Example). Set 9600 serial parameters, n, 8, 1.

To send an SMS type the command AT + CMGS = nnnnnnnn
Wait for prompt, type the message text and close with

To receive the message, type the commands:
AT + CPMS = SM, SM, SM (Use SIM for reading, writing and storing messages)
AT + CMGF = 1 (Text reading mode)

Now when you receive a message use the commands:
AT + CMGL = ALL (Read all messages)
AT + CMGR = 1 (Read message 1 only)
AT + CMGD = 1 (Delete message 1)

[Sergio Bertana]

With reference to the previous post where the customer complained of not reading the SMS messages received, I refer to the command AT + CPMS “Preferred SMS message storage”. With this command you can define which memory to use for message management. The command has 3 parameters, 2 of which are optional, AT + CPMS = [, [, ].

Indicates the memory used by the list, read, and delete messages commands.
Indicates the memory used by the commands for writing and sending messages.
Indicates the memory used for storing received messages.

The possible types of memory are:

“SM” SIM, SIM memory
“ME” Mobile Equipment, modem memory
“MT” Both memories are used by increasing the number of messages that can be stored.

Now from what has been described, it is important for reading and deleting received messages that the types of memory shown in is are coincident. I recommend defining the SIM memory as a storage area for all 1 memories. Send the command to the modem: AT + CPMS = SM, SM, SM.

The setting made with the command is stored in the non-volatile memory of the modem, therefore the setting made remains permanently active.

[Sergio Bertana]

I add notes on managing SMS messages. To set the service center number use the command AT + CSCA = nnnnnn "SMS service center address".

I report the numbers of some service centers:
Service Center TIM messages: + 393359609600
Vodafone Messages Service Center: + 393492000200
Wind Service Center: + 393205858500

[Alberto]

For information (after several days of testing) I would like to point out that the modem GSM BGS2 and the card of the 3 they are not compatible.
In fact, by trying with a Vodafone SIM or TIM the modem works correctly.

[Author]

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