# * AT+QMTOPEN=0,"base.codestudios.cn",1883* AT+QMTCLOSE=0 * AT+QMTCONN=0,"BC20"* AT+QMTDISC=0 * AT+QMTSUB=0,0,"demo",0* AT+QMTUNS=0,"demo" * AT+QMTPUBEX=0,0,0,0,"4g",4* ABCD