说明：  发送AT+CMGS= YYY [CR] 其中 YYY 为TPDU的十进制长度 收到[>][SP]响应后再发送 [SCA][TPDU][ctrl-Z]
(Send AT+ CMGS = YYY [CR] one of metric YYY for the length of the TPDU received [> ] [SP] and then sent in response to [SCA] [TPDU] [ctrl-Z])