TC35i GSM With PIC 16F690 help

[financecatalyst]

After a long time, but I would like to ask here as well as you lot have worked with TC35i:

* Are there any AT commands for this or how to see the keyed in number from the mobile keypad on the other end during an active voice call. MY TC35i is connected to my comp with RS232. I am watching and sending normal AT commands using hyperterminal.

Currently what happens is that I dial the modem using my mobile, hyperterminal shows RING ****, I send ATA, and call gets answered and OK appears. After that when I press any number on the keypad, nothing appears on the hyperterminal.

Hope to crack this problem here soon. Thanks

[aratti]

Numbers are encoded in the DTMF signal. If you need to read them you have to decode the dtmf sound signal. The easiest way is to use a MT8880.

Cheers

Al.

[financecatalyst]

Thanks Al. Though I will search on this IC now, but I am a little confused as to the connections of this IC. What I mean is I have used TX/RX lines from RS232 already, where would this DTMF IN/OUT will connect to? I have come across few circuits but this IC is connected to home phone line rather than MODEMS.

[aratti]

The DTFNM input that normally is connected to the phone line, must be connected to the voice out of your TC35i. Generally one capacitor of 100 nF and 100 Khoms in series is just enough. See the examples on the data sheet. The decoding is presented as a nibble ( 4 bits).

Cheers

Al.

[Demon]

Moved from Schematics.

Robert