AT+CIPSHUT
SHUT OK
AT+CLPORT="TCP","2021"
OK
AT+CLPORT?
TCP: 2021
UDP: 3030
OK
AT+CGATT=1
OK
AT+CGDCONT=1,"IP","airtelgprs.com"
OK
AT+CDNSCFG="122.160.120.56","202.56.230.7"
OK
AT+CDNSCFG?
PrimaryDns:122.160.120.56
SecondaryDns:202.56.230.7
OK
AT+CSTT="airtelgprs.com","",""
OK
AT+CIICR
OK
AT+CIFSR
106.202.129.64
AT+CIPSTATUS
OK
STATE: IP STATUS
AT+CIPHEAD=1
OK
AT+CDNSORIP=1
OK
AT+CIPSTART="TCP","ftp.microchip.com","21"
OK
CONNECT OK
+IPD27:220 Microsoft FTP Service
> ls
SEND OK
+IPD34:500 'LS': command not understood