USE_CFG=1
AGC_MODE = 1
RING_THRESHOLD =800
PLAY_DEVICE=1
RING_DETECT_DELAY_TIME = 1
DTMF_RCV_THRESHOLD=600
FILTER_DRIVER_MODE=0

spec:
USE_CFG  = 1,means use this config file.
AGC_MODE = 1,use agc function. default=1;=0,no agc;=2,double agc
RING_THRESHOLD = 200-2000.    default=800
PLAY_DEVICE:0=NO, 1=System, 2=USB 
RING_DETECT_DELAY_TIME = 0-3，单位是秒，Unit is Second
DTMF_RCV_THRESHOLD,DTMF接收灵敏度，缺省值为600；范围为（300－4000）
FILTER_DRIVER_MODE,过滤驱动模式，=1启用，＝0使用无驱动模式。

