[Asterisk-Users] What does RELAXDTMF do?

[Peter J Dean]

I have an issue with DTMF. DTMF is being partly recognised by some  
external IVR systems (banks, billing, etc), other IVR systems have  
intermittent issues. Call our VSP directly and using their IVR system  
without issue, and our internal IVR works just fine. Currently i have  
all voip devices using RFC2833, which is what is recommended, and  
thus the sip.conf file has dtmfmode=rfc2833 and relaxdtmf=yes.

I have not seen any information that clearly defines the purpose of  
the relaxdtmf parameter in the sip.conf file, and wondering of  
flicking it from yes to no will have an impact, and if so what sort  
of impact will it have?

Redhat FC4 + updates
Asterisk v1.2.9.1
SNOM v6.0.3 beta
SPA3000 v3.1.10d