asterisk/configs/samples/dsp.conf.sample

[default]
;
; Length of sound (in milliseconds) before a period of silence is considered
; to be a change from talking to silence or a period of noise converts silence
; to talking.  [default=256]
;
;silencethreshold=256

; DTMF Reverse Twist and Normal Twist is the difference in power between the row and column energies.
;
; Normal Twist is where the row energy is greater than the column energy.
; Reverse Twist is where the column energy is greater.
;
; Power level difference between frequencies for different Administrations/RPOAs
;               Power Gain              equiv
;               normal  reverse         dB's
; AT&T(default) 6.31    2.51            8dB(normal), 4dB(reverse)
; NTT           3.16    3.16            Max. 5dB
; Danish        3.98    3.98            Max. 6dB
; Australian    10.0    10.0            Max. 10dB
; Brazilian     7.94    7.94            Max. 9dB
; ETSI          3.98    3.98            Max. 6dB

;previous version compatible AT&T values
; RADIO_RELAX disabled, and relaxdtmf=no
;               6.30    2.50            7.99dB(normal), 3.98dB(reverse)
; RADIO_RELAX disabled, and relaxdtmf=yes
;               6.30    4.00            7.99dB(normal), 6.02dB(reverse)
; RADIO_RELAX enabled, and relaxdtmf=no
;               6.30    2.50            7.99dB(normal), 3.984dB(reverse)
; RADIO_RELAX enabled, and relaxdtmf=yes
;               6.30    6.50            7.99dB(normal), 8.13dB(reverse)

;If you don't know what these mean, don't change them.
;dtmf_normal_twist=6.31
;dtmf_reverse_twist=2.51
;relax_dtmf_normal_twist=6.31
;relax_dtmf_reverse_twist=3.98

;successive number hits/misses of 12.75ms before a digit/nodigit is considered valid
;dtmf_hits_to_begin=2
;dtmf_misses_to_end=3