make voice call from a mobile using AT command

[nshakeeb]

I want to make voice call from a mobile using AT command

I have used following sequences from hyperterminal

1. AT
OK
2. ATZ
OK
3. ATDxxxxxxxxxxx [ here xxxxxxxxxx is a phone number ]
NO CARRIER

It tries to dial but gives output "Carrier not found"


but this AT commands works fine for normal PSTN modem

Anyone has idea how this can be done