[Hilo] How to disconnect a voice/data call by DTR drop?

Answer: Please set <AT+CVHU=2> and <AT&D2>, then you can hang up a voice call or data call by toggle DTR signal. For example:
AT+CVHU=2
OK
AT&D2
OK
ATD10086;
OK
NO CARRIER ----Disconnect the voice call by DTR drop.