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 Column energy is greater than the Row energy
; Reverse Twist is where the Row 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