How do I know, that the other phone has answered my call?

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Hi Syeda Anila or anyone :-)
I am a beginner to using an AT modem for building a mobile application with Arduino.
Can you tell me just one simple answer.
I dial a phone number by
ATD774922910;

The modem is ringing and expects the other phone to answer, which is hopefully done by
ATA;

But I am not personally listening to the call, so how does the application know, that the other phone has answered the call and is listening?

I receive a message like:
BUSY
or
NO CARRIER
or
NO ANSWER
when the call is over. But that is another thing.

What I have tried:

I have tried the
AT+CPAS
command, but it returns
+CPAS: 4
no matter if I am still ringing or the other phone has answered the call

Posted 24-Mar-18 17:47pm

Member 13745038

Updated 24-Mar-18 21:32pm

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Peter_in_2780 · Answer 1 · 2018-03-24T21:06:00

Solution 1

If your call succeeds (is answered by a compatible modem), then in place of BUSY or NO ANSWER or whatever, you will receive CONNECT (often followed by more information, such as the baud rate).

Posted 24-Mar-18 21:06pm

Peter_in_2780

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Member 13745038 25-Mar-18 14:46pm

Hi, thank you for kindly answering my question.
This actually did not happen in my application (no CONNECT message).
Do you have a documentation that describes the "CONNECT" message in a voice call?
As I read in https://www.multitech.net/developer/wp-content/uploads/2010/10/S000463C.pdf
the message CONNECT <speed> works only for data call.
Since I am deep down in anyone elses software, I have no possibility to connect the modem to a terminal and check what really happens.
Can anyone verify this simple modem communication in a real voice call?
Just to clarify - I need a message, when the other phone answers the ringing and goes in the voice mode.
Thank you very much.

Peter_in_2780 25-Mar-18 16:35pm

As far as I know, ATD.... is used to establish a data call. I suggest you have a look at https://en.wikipedia.org/wiki/Voice_modem_command_set for more hints about how to set up voice calls.

Member 13745038 25-Mar-18 21:10pm

Hi Peter.
According to the S000463C.pdf (see the complete link above) the ATD is used for both voice and data call (the ; at the end makes the voice call). I am using the Arduino GPRS modem shield with a SIM card to make call to mobile phones.

But no matter what. I actually built a simple terminal environment by now, to see the messages in the communication. And there is no message whatsoever when the receiving party picks up the phone. This is ridiculous, but that's the way it is right now.

I have had a look at the Wikipedia document, but that is for ancient voice modems. My modem answers to AT+FCLASS=? with (0, 1)

But anyway, thank you for being with me so far :-)

Is there anyone who used the GPRS modem perhaps for building a mobile phone?