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Harald Welte gerrit-no-reply at lists.osmocom.orgHarald Welte has submitted this change and it was merged. ( https://gerrit.osmocom.org/11171 ) Change subject: mncc: add note about DTMF considerations ...................................................................... mncc: add note about DTMF considerations Add an informative note on how DTMF signalling is done in mobile networks and mention the limitations regarding DTMF, when internal MNCC is used. Change-Id: Iedcf4ad5e0e4697c6a05ebdd4f43173c14c7c448 Related: OS#2777 --- M common/chapters/mncc.adoc 1 file changed, 26 insertions(+), 0 deletions(-) Approvals: Jenkins Builder: Verified Harald Welte: Looks good to me, approved diff --git a/common/chapters/mncc.adoc b/common/chapters/mncc.adoc index 8825be3..3adbf7f 100644 --- a/common/chapters/mncc.adoc +++ b/common/chapters/mncc.adoc @@ -60,6 +60,32 @@ Router. More widespread integration of external call routing is available via the OsmoSIPConnector. + +=== DTMF considerations + +In mobile networks, the signaling of DTMF tones is implemented differently, +depending on the signaling direction. A mobile originated DTMF tone is +signaled using START/STOP DTMF messages which are hauled through various +protocols upwards into the core network. + +Contrary to that, a mobile terminated DTMF tone is not transfered as an out of +band message. Instead, in-band signaling is used, which means a tone is injected +early inside a PBX or MGW. + +When using {program-name} with its built in MNCC functionality a mobile +originated DTMF message will not be translated into an in-band tone. Therefore, +sending DTMF will not work when internal MNCC is used. + +For external MNCC, the network integrator must make sure that the back-end +components are configured properly in order to handle the two different +signaling schemes depending on the signaling direction. + +NOTE: osmo-sip-connector will translate MNCC DTMF signaling into sip-info +messages. DTMF signaling in the opposite direction is not possible. +osmo-sip-connector will reject sip-info messages that attempt to signal +a DTMF tone. + + === MNCC protocol description The protocol follows the primitives specified in 3GPP TS 04.07 Chapter 7.1. -- To view, visit https://gerrit.osmocom.org/11171 To unsubscribe, or for help writing mail filters, visit https://gerrit.osmocom.org/settings Gerrit-Project: osmo-gsm-manuals Gerrit-Branch: master Gerrit-MessageType: merged Gerrit-Change-Id: Iedcf4ad5e0e4697c6a05ebdd4f43173c14c7c448 Gerrit-Change-Number: 11171 Gerrit-PatchSet: 1 Gerrit-Owner: dexter <pmaier at sysmocom.de> Gerrit-Reviewer: Harald Welte <laforge at gnumonks.org> Gerrit-Reviewer: Jenkins Builder (1000002) -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.osmocom.org/pipermail/gerrit-log/attachments/20181003/1d5a4d5a/attachment.htm>