Aug 3, 2015. SIM800 Series_AT Command Manual_V1.09. 2. 2015-08-. 1.4.1 Basic syntax. 1.4.4 Combining AT commands on the same Command line. Commands to specify music playing, as well as how to play music and other. The audio data is sorted by folder; supports up to 100 folders, each folder can be . ATO SWITCH FROM COMMAND MODE TO DATA MODE/PPP ONLINE MODE. AT+VTSEX PLAY SPECIAL DTMF AND TONE.