I’m using a GR64 for GPRS and GSM. I’ve issued a command ATD07827984793, and have got an unsolicited ECAV response of ECAV 1,0,2,8,28.
According to the manual, the ‘28’ means ‘Invalid number format (incomplete number)’. But what is wrong with the number? It looks fine to me and I can call it from a telephone without problem.