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DTMF tones

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MCSUSER

Technical User
Apr 2, 2009
31
CA
Hi all,
We have DTMF issue when accessing the third party vm system. We have CS1000 REL 5.0. Does anyone know, how the DTMF tones are sent on the network. Is it inband(DTMF within the RTP) or out-of-band (MGCP signalling). If out-of-band, would it be possible to debug the MGCP signalling to find out if the DTMF signall are sent out on the network?.
Thanks in advance.
 
I've found this below.

1)UNABLE TO USE MF TONES ON DIGITAL SETS.MERIDIAN MAIL
2)Trunks Unable to send MF tones to line.

1)check ld 97. type=xctp dtmf=138
2)ld 14 supn=no

38 IS FOR UK MF TONES (14 IS FOR USA MF TONES)

Trunks Unable to send mf tones to line.
If a customer needs to send mf to line for ie Voice Menu Services , Supervision on the TRUNKS may need to be set to NO ( Ovl 14 SUPN - NO )
This is due to a reversal to indicate csa is no longer guaranteed for all PSTN calls.
Setting SUPN to No can affect call logging. It may be necessary to change Ovl 16 OAN to NO .

All the best

Firebird Scrambler
Meridian Programmer in the UK

If it's working, then leave it alone!.
 
I've also spotted this below

CS1000 rls 5
IP set calls out over ISDN30e to a Vodaphone mobile which diverts on no answer to the Vodaphone voicemail facility. The caller hears the greeting ending with ..."please leave your message after the tone" but the tone is never heard.
Callers from TDM sets do hear the tone
Callers to O2 mobiles do hear the tone if diverted to voicemail (can't explain this..)

Resolution: uncheck the 'DTMF tone detection' box on Element Manager under MGC/VGW and IP Phone codec profile. The same option can also be found under the IP Node config/VGW and codecs/Signalling options - relevant if VGW media cards are being used.



Extract from the IP Peer Networking Installation and Commissioning NTP:

Note: In-band DTMF tones that originate from an analog
(500/2500-type) telephone or incoming trunk are filtered out of the
media stream by the DSP of the Voice Gateway Media Card. This is so
that double detection of the DTMF digits does not occur. This causes
additional delay in the speech path due to the buffering required to
ensure that no DTMF tones get through the filter.

In-band signaling
In-band DTMF tones are sent as RTP packets over the RTP channels. This
method of transporting DTMF tones is inherently unreliable as RTP packets
can be lost over the network. However, this method is quite reliable if a
G.711 codec is used for the transmission.

For CS 1000 systems, the in-band DTMF tones can be sent only from an
analog (500/2500-type) telephone with tone detection turned off for the
Voice Gateway Media Card.


See NTP NN43001-313 for more information on tone-handling in an IP environment


All the best

Firebird Scrambler
Meridian Programmer in the UK

If it's working, then leave it alone!.
 
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