ATD+3900000000;< CR>

To call a phone number in the international format(the zeros represent the number while < CR > it is equivalent return to ascii decimal 13)

ATD>x< CR>

To call number x from the phone book in the SIM Card.
But WARNING, in this last case the following settings are necessary:

AT+CPBS="SM"< CR > // To activate the SIM Card (instead of the phone memory)

AT+CPBF="Friend"< CR > // For read the Friend's index number (with which it's saved in the SIM Card)

AT+FCLASS=8< CR > // For setting a VOICE call

AT#CAP=2< CR > // To disable the headphone (internal audio path)

AT+CLVL=8< CR > // Set the volume

AT+CMUT?< CR > // Make sure that the microphone is not set to MUTE (response = 0)

and finally

ATD>x< CR>

Oh... I forgot, when you have ended remember to hang!

ATH< CR > // hang-up

The commands used are drawn from releasable detailed lists AT COMMAND from the Telit GM862 site

http://www.telit.co.it/modules.asp