[Asterisk-doc] rfc2833 and Grandstream

[Randy Resnick]

Common Issues -> DTMF over SIP

"Users of Grandstream phones should use Info for the Asterisk voicemail; 
the other methods won't work."

"rfc2833 is similar to Info, but will not work on Grandstream phones."

I don't think this is still true since I've been using rfc2833 since 
I've owned the BT101 and 102, several months.

A general suggestion:

replace:
"DTMF (Dual-Tone Multi-Frequency) is the name for the specific sounds 
("dial tones") made by the keys on a telephone keypad. The choice of 
which method to use for DTMF over SIP is made in Asterisk's 
/etc/asterisk/sip.conf. Carrying DTMF over SIP can be done in one of 
three ways:"

with:
"DTMF (Dual-Tone Multi-Frequency) is the name for the specific sounds 
("dial tones") made by the keys on a telephone keypad. If the wrong 
method is used, one possible symptom is that tones transmitted will have 
no effect. The choice of which method to use for DTMF over SIP is made 
in Asterisk's /etc/asterisk/sip.conf and will probably require 
configuration of the phone itself. Carrying DTMF over SIP can be done in 
one of three ways:"

--
rr