asterisk users - Feb 2012 - Spurious DTMF recognition problems.

Hi,

in asterisk 1.6.2.16 I get spurious DTMF recognition over SIP from an
Audiocodes.
I think the DTMF recognition is the Audiocdes' fault, the Audiocodes log
seems to say so as well, but I
want to make sure, and fixing the Audiocodes is not an option in this particular
case - don't ask.

Can someone explain to me what the following means *exactly*

[Feb 10 21:15:40] DTMF[2538] channel.c: DTMF begin 'A' received on
SIP/sip-out-3-0003a606
[Feb 10 21:15:40] DTMF[2538] channel.c: DTMF begin passthrough 'A' on
SIP/sip-out-3-0003a606
[Feb 10 21:15:40] DTMF[2538] channel.c: DTMF end 'A' received on
SIP/sip-out-3-0003a606, duration 12 ms
[Feb 10 21:15:40] DTMF[2538] channel.c: DTMF end accepted with begin 'A'
on SIP/sip-out-3-0003a606
[Feb 10 21:15:40] DTMF[2538] channel.c: DTMF end 'A' detected to have
actual duration 59 on the wire, emulation will be triggered on
SIP/sip-out-3-0003a606
[Feb 10 21:15:40] DTMF[2538] channel.c: DTMF end 'A' has duration 59 but
want minimum 80, emulating on SIP/sip-out-3-0003a606
[Feb 10 21:15:40] DTMF[2538] channel.c: DTMF end emulation of 'A' queued
on SIP/sip-out-3-0003a606

Does this mean asterisk's DSP recognizes this inband in the audiostream?
Can this also be RFC2833 sent by the audiocodes?
Is there some way I can stop this in asterisk, maybe disable detection of the
'A' through 'F' digits in the sourcecode?

The setting 'dtmfmode', is it only used on outgoing DTMF? In other words
if I set a SIP peer to inband, will incoming RFC 2833
format DTMF still be detected/accepted by asterisk?

thanks for any help,
Antonio.