[cisco-voip] DTMF conversion paired with transcoding functionality - C3945E

[Maciej Bylica]

Hello,

I have CUBE 3945E running IOS ver 15.1.
I've been trying to configure hw transcoding and dialpeers to have
codec/dtmf/fax transcoding capabilities up and running.
Transcoding section looks like following:


voice-card 0
 dsp services dspfarm
!
voice service voip
 address-hiding
 allow-connections sip to sip
 no supplementary-service sip moved-temporarily
 no supplementary-service sip refer
 fax protocol t38 version 0 ls-redundancy 0 hs-redundancy 0 fallback
pass-through g711alaw
 sip
  midcall-signaling passthru
!
voice class codec 1
 codec preference 1 g729br8
 codec preference 2 g729r8
 codec preference 3 g711alaw
!
voice class codec 2
 codec preference 1 g711alaw
 codec preference 2 g711ulaw

sccp local GigabitEthernet0/0
sccp ccm 10.10.10.3 identifier 1 version 4.0
sccp
!
sccp ccm group 48
 description testowy
 bind interface GigabitEthernet0/0
 associate ccm 1 priority 1
 associate profile 20 register sxcoder
 keepalive retries 5
 switchover method immediate
 switchback method immediate
 switchback interval 15
!
dspfarm profile 20 transcode universal
 description testow dsp profil
 codec g729abr8
 codec g729ar8
 codec g729r8
 codec g729br8
 codec g711alaw
 codec g711ulaw
 maximum sessions 15
 associate application SCCP
!
telephony-service
 sdspfarm units 1
 sdspfarm transcode sessions 128
 sdspfarm tag 1 sxcoder
 max-ephones 1
 max-dn 1
 ip source-address 10.10.10.3 port 2000
 max-conferences 1 gain -6
 transfer-system full-consult

and it works.
The problem i have is associated somehow with DTMF conversion from
RFC2833 to G711 inband.

!
dial-peer voice 1 voip
 description INCOMING dial-peer
 destination-pattern 4822T
 session protocol sipv2
 session target ipv4:10.10.10.2
 voice-class codec 1
 dtmf-relay rtp-nte
!
dial-peer voice 2 voip
 description OUTGOING dial-peer
 destination-pattern 4855+
 session protocol sipv2
 session target ipv4:10.10.10.4
 voice-class codec 2
 fax protocol pass-through g711alaw
!

All calls matched with dialpeer 1 and 2 are being transcoded.
It doesn't matter if there are no dtmfs running back and forth.
Is there any chance to differentiate that behavior and for pure voice
call (without dtmf signals) do not use transcoding (while codec G.711
to codec G.711) but only for ivr type of connections where dmtfs are
needed?
Lets assume that we cannot differentiate dialpeers by callig/called number.

What is more interesting i've just use Inband dtmf in inband call
attempt and transcoding was triggered exactly as previously.

What did I miss?

Thanks in advance.
Maciej.