[Hilo] Why <AT+KTCPSTART=1 failed with a new SIM card?

[Hilo] Why <AT+KTCPSTART=1> always return “NO CARRIER” with a NEW SIM card, but returns OK after I use the same SIM card in another device?

Answer: The GPRS may not be really attached. Please use <AT+CGATT=1> even you see <AT+CGATT?> returns <+CGATT: 1> (attached to GPRS).