[Asterisk-Users] Sipura SPA-3000 and PSTN dtmf

[Arsen Chaloyan]

Vahan,

see my comments below.

>Greetings,
>
>What is the recommended settings for using SPA-3000's
>FXO port for 
>dialing out to PSTN in regard of the DTMF?
>
>The voip lan contains SPA-2100 and SPA-3000, with all
>fxs/fxo ports 
>registered to the Asterisk box with unique
>username/passwords.

>The inbound PSTN DTMF works excellently, e.g. people
>calling from PSTN 
>into the * box are able to pick IVR items with DTMF
>reliably.
exactly!

>
>The problem manifests itself when you attempt to
place >a call via 
>SPA-3000's FXO into PSTN to a different IVR system
and >try to navigate 
>its menu. Audibly, the other end hears very short
DTMF >bursts with short 
>silence afterwards, as like SPA-3000 detects a DTMF,
>mutes it and sends 
>rfc2833 or whatever. Obviously, the burst is short
>enough to be ignored 
>by the remote IVR system (similar Asterisk/SPA-3000
>setup).
Actually SPA-3000 should receive rfc2833 DTMF events
from IP side and put inband DTMFs instead to PSTN
side.

SPA-3000 fails to correctly detect rfc2833 events,
which poorly constructed by asterisk.

So asterisk isn't fully compliant to rfc2833, from the
other hand other VoIP gateways (but not SPA-3000)
manage to detect rfc2833 DTMFs from asterisk.

SPA-3000 serves well in this scenario if source of RTP
stream is another VoIP device or phone (cisco, snom,
aastra...), not asterisk itself.

Here come the solution:
try to exclude asterisk from media path
canreinvite=yes

[111]
;SPA-3000 FXO port
type=friend
username=111
secret=xxx
host=dynamic
canreinvite=yes
dtmfmode=rfc2833

This is the only way I manage to setup
asterisk/SPA-3000 in described scenario.

Hope this will help,
Arsen.

>
>The relevant settings in the SPA-3000/2100 config for
>DTMF are set to 
>'Auto' setting.
>
>The relevant lines in sip.conf:
>
>;-------
>[general]
>;irrelevant lines removed
>dtmfmode=rfc2833
>disallow=all
>allow=alaw
>allow=ulaw
>allow=g729
>
>[111]
>;SPA-3000 FXO port
>type=friend
>username=111
>secret=xxx
>host=dynamic
>
>[112]
>;SPA-3000 FXS port
>type=friend
>username=112
>secret=xxx
>host=dynamic
>
>[113]
>;SPA-2100 FXS1 port
>type=friend
>username=115
>secret=xxx
>host=dynamic
>
>[114]
>;SPA-3000 FXS2 port
>type=friend
>username=114
>secret=xxx
>host=dynamic
>;-------
>
>
>Should I instead split the SPA-3000's FXO entry into
a >type=user and 
>type=peer entries with the first having
>dtmfmode=rfc2833 and second 
>dtmfmode=inband?
>
>Which is the proper way of sending inband dtmf over
>g711 into the PSTN?
>
>
>Awaiting assistance and thanks for your time,
>Vahan

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