My ATD couldn't send any data

Hi all,

i’m using Supreme 20 in my research, but i have a slight problem with it. i tried to send data to another fastrack 20 modem.
i’m using the ATD. without ‘;’ because i want to send data not using the call function. but the response was

could someone give me a clue about this problem? thanx a lot.

Hi edy2,
Are you sure that your simcards have data call feature?

What do you mean by that?

Thanx for the quick replies,
yes my SImcard has the function to send data.
I mean that i want to use the ATD command to send the data, not as the call function. since the only difference between the call function and sending data is the ‘;’ mark in the end of the command.

i have an opinion, maybe there is some parameter or register value that i should have set up first before i use my modem to send data. is there such a parameter?


ATD is the command to Dial a number to establish a call; that’s all it does - it does not send any data once the call is established!

Once the call is established (as indicated by the CONNECT response), you need some kind of Application to actually send any data!

No, that is not correct - see ablve.

But bevor that, checkif you have entered the SIM-PIN number and the LED is blinking (to indicate it has a network connection)

Not that both SIMs need to be data-enabled…

i’m using the same SIM for both of my modem. all i want to do is to connect both of my modem using the ATD function to send data or fax. if you read the AT COmmand user guide u will find that ATD has 2 function. yes my LED light is blinking, and i tested it again by using it to made a call to my cellphone and it went perfectly.
i’ve read the user again yesterday and i found out about the AT+CBST AT COmmand. it is said that the command was to change the data type sent by the ATD command. am i get it right?

Thank you for your explanations.

The ATD command establishes the connection, and nothing else.

Once the connection is established, you need something else to actually send the data!

This is exactly the same as with a standard PSTN (landline) modem - nothing GSM-specific here.

Was that a data call, or a voice call?

Not quite: again, ATD establishes a connection; it does not send any data over that connection.
Thus, AT+CBST affects the type of the connection established by ATD.

Yes, you may need to adjust the AT+CBST settings to suit the particular network(s) that you are using; eg, see viewtopic.php?f=34&t=1622&p=5882&hilit=cbst

i’m using ATD to make a voice call to my cellphone. it worked. and when i said data, the data is just a character which when i type it on my modem. the same character was sent and appear in the other modem. not the big size data type. are there any other way to do this kind of function? the concept is really simple. i just want to send every character that i type on my computer to the other computer (in hyper terminal) using the Wavecom modem.

SO you have not shown that your SIMs support Data calls, then, have you?

The question you were asked was, “do your SIMs support Data calls”

If your SIMs don’t support Data calls, then you will not be able to send Data between your modems!

You need to confirm whether or not your SIMs support Data calls