Первое ,что дал поиск в гугл
пример применения AT-команды:

AT+CIPSTART=?

+CIPSTART: ("TCP","UDP"),("(0,255).(0,255).(0,255).(0,255)"), (1,65535)
+CIPSTART: ("TCP","UDP"),("DOMAIN NAME"),(1,65535)

OK

Start a TCP connection
AT+CIPSTART="TCP","116.228.221.51","8500"

OK

Start a UDP connection
AT+CIPSTART="UDP","116.228.221.51"."9600"

CONNECT OK