hi everyone

now, i'm working with a gprs modem, its name is maestro 100, Wavecom. i have a problem.
when i set up some command on this modem such as : AT+CGDCONT = 1,"IP",'internet"
AT+CGATT=1, it return OK, so when i set command AT+CGACT it return ERROR. and when i use command ATD(mynumber) it displayed as folowing:
OK
at+cgatt=1
OK
at+cgact=1
ERROR

atd*99#
CONNECT 115200
~�}#�!}!}!} }6}!}$}%�}"}&} } } } }'}"}(}"}#}$�#&ܴ~~�}#�!}!}!} }6}!}$}%�}"}&} } ~
NO CARRIER
But i don't know why. and i can't send message or call. I can't debug that.
Everyone can help me.
thanks