[Freeswitch-dev] FXS bridged on FXO ports and DTMF - Deja Vu
Moises Silva
moises.silva at gmail.com
Mon Jun 28 15:54:19 PDT 2010
Hello,
I spent a few hours playing with DTMF stuff and analog cards and it seems
there is 2 issues at hand.
1. Bleeding DTMF.
2. Echo DTMF.
The first issue, for software DTMF, can be solved with Anthony's pre buffer
size feature. However that introduces delay by design, and it will not work
for large DTMFs (if the dtmf is larger than the buffer).
For hardware DTMF a new driver was just released that includes a
configuration to allow the EC chip to perform the dtmf tone removal which
cuts down the bleeding to only 20ms (in my testing) there is no way a DTMF
detector will consider that a valid DTMF and therefore the bleeding should
be solved with no delay introduced. The option is HWEC_DTMF_REMOVAL = YES,
must be added along with the usual TDMV_HW_DTMF = YES in wanpipex.conf
Ideally the software DTMF detector (in this case teletone) should cut it at
the same time that it detects it. I thought may be spandsp would help, but
it seems spandsp does not have an option to squelch the dtmf tone. May be
Steve can help with that. I pinged him on IRC and he said he may get some
code working, but there is no date for that and also that would involve
integrating spandsp into FreeTDM, any reason to not do this now that spandsp
is LGPL?
As for the echo dtmf. It seems sometimes an outgoing DTMF may be detected as
incoming DTMF due to echo. There is not much we can do there if you don't
have echo cancellation. If however you have this issue even with HW EC, call
Sangoma tech support and we will be happy to look at the issue.
In another note, I added a variable and application to disable DTMF.
<action application="disable_dtmf"/>
That will disable DTMF (either software or hardware) in the leg executing
that app. If you want to disable in the outgoing leg (before a bridge), you
must export a special variable:
<action application="export" data="freetdm_disable_dtmf=yes"/>
The DTMF is enabled automatically on each call, so there is no need to
enable it for each call. But in case you need to enable it:
<action application="enable_dtmf"/>
Moises Silva
Senior Software Engineer
Sangoma Technologies Inc. | 50 McIntosh Drive, Suite 120, Markham ON L3R 9T3
Canada
t. 1 905 474 1990 x 128 | e. moy at sangoma.com
On Wed, Jun 16, 2010 at 12:09 PM, Anthony Minessale <
anthony.minessale at gmail.com> wrote:
> openzap_pre_buffer_size is a variable you can set to specific number of MS
> 60 for example.
> it will pre_buffer the audio on the channel so when you detect dtmf it will
> completely drop the buffer so all of the original
> dtmf should be dropped as well. probably if the dtmf is too long then it
> will cause problems anyway.
>
> if that pre buffer does not fix anything it would point to echo or
> bleeding.
>
> We could make a variable to disable dtmf detection completely on a per-call
> basis possibly but you will still probably hear it bleeding.
>
> This type of problem was reported fixed with sangoma because of the
> echo canceler.
> I don't use dahdi or digium stuff much so I can't comment on what happens
> when you use it.
>
>
>
> On Wed, Jun 16, 2010 at 3:41 AM, François Legal <devel at thom.fr.eu.org>wrote:
>
>> Does this really fix it ?
>> I wonder because the problem I see here is also that the FXS side detects
>> the DTMF and then queues it on the FXO side for generation. That leads to
>> the called party receiving twice the DTMF, the first one is the inband
>> DTMF, the second is the one queued/generated by the FXO channel.
>>
>> For a clean fix, I guess some kind of application should be created, that
>> would prevent DTMF to be queued on the other channel. Such application
>> would then be called before the bridge. Maybe there is a cleaner way to do
>> this.
>>
>> François
>>
>> On Tue, 15 Jun 2010 18:23:13 -0500, "Jeroen C. van Gelderen"
>> <jeroeng at thegreek.com> wrote:
>> > Hi everybody,
>> >
>> > I have a problem that is very similar to a problem
>> > reported by François [1] except for the fact that
>> > my FXS and FXO ports are on a Xorcom Astribank
>> > device instead of a Sangoma.
>> >
>> > To quote François: "The problem is that each leg of
>> > the bridge is detecting the inband DTMF, and so
>> > [F]reeswitch sends each detected DTMF from one leg
>> > to the other, and so on and so forth (as each leg
>> > detects the DTMF again and again)"
>> >
>> > HIS words but evidenced by the MY log :)
>> >
>> > The snippet below has DTMF coming in on the FXS port
>> > (1:1) and bouncing between it and the FXO port (3:1).
>> > The ports are simply bridged together with
>> >
>> > "bridge(OpenZap/3/1/F)" or "bridge(OpenZap/3/1/w)"
>> >
>> > I'm running:
>> >
>> > FreeSWITCH version: 1.0.head (git-01c0c69 2010-06-08 16-22-21 -0500)
>> > dahdi: Version: SVN-trunk-r8762
>> >
>> > Output of lsdahdi at end of message.
>> >
>> > ----8<----8<----8<----8<----8<----8<----8<----
>> > [...]
>> > 2010-06-13 04:18:39.217256 [DEBUG] mod_openzap.c:721 queue DTMF [4]
>> > 2010-06-13 04:18:39.256255 [DEBUG] zap_io.c:2062 3:1 GENERATE DTMF [4]
>> > 2010-06-13 04:18:39.397253 [DEBUG] mod_openzap.c:721 queue DTMF [4]
>> > 2010-06-13 04:18:39.439252 [DEBUG] mod_openzap.c:780 Dropping frame!
>> (write
>> > not ready)
>> > 2010-06-13 04:18:39.439252 [DEBUG] zap_io.c:2062 1:1 GENERATE DTMF [4]
>> > 2010-06-13 04:18:39.637249 [DEBUG] mod_openzap.c:721 queue DTMF [4]
>> > 2010-06-13 04:18:39.676248 [DEBUG] zap_io.c:2062 3:1 GENERATE DTMF [4]
>> > 2010-06-13 04:18:39.859244 [DEBUG] mod_openzap.c:780 Dropping frame!
>> (write
>> > not ready)
>> > [...ad infinitum...]
>> > ----8<----8<----8<----8<----8<----8<----8<----
>> >
>> > Because I needed DTMF pass-through working "now"
>> > I applied an ugly HACK. This drops DTMF tones
>> > detected on spans 3 and 4 (which are my FXO
>> > spans). This is very WRONG but it does solve
>> > my immediate problem:
>> >
>> > ----8<----8<----8<----8<----8<----8<----8<----
>> > diff --git a/libs/openzap/mod_openzap/mod_openzap.c
>> > b/libs/openzap/mod_openzap/mod_openzap.c
>> > index 5aebfea..ff3b081 100644
>> > --- a/libs/openzap/mod_openzap/mod_openzap.c
>> > +++ b/libs/openzap/mod_openzap/mod_openzap.c
>> > @@ -718,8 +718,12 @@ static switch_status_t
>> > channel_read_frame(switch_core_session_t *session, switch
>> > for (p = dtmf; p && *p; p++) {
>> > if (is_dtmf(*p)) {
>> > _dtmf.digit = *p;
>> > - zap_log(ZAP_LOG_DEBUG, "queue DTMF
>> [%c]\n",
>> > *p);
>> > - switch_channel_queue_dtmf(channel,
>> &_dtmf);
>> > + if (tech_pvt->zchan->span_id == 3 ||
>> > tech_pvt->zchan->span_id == 4) {
>> > + zap_log(ZAP_LOG_DEBUG, "Ignoring
>> > DTMF [%c] on FXO port %d:%d\n", *p, tech_pvt->zchan->span_id,
>> > tech_pvt->zchan->chan_id)
>> > ;
>> > + } else {
>> > + zap_log(ZAP_LOG_DEBUG, "queue
>> DTMF
>> > [%c]\n", *p);
>> > +
>> switch_channel_queue_dtmf(channel,
>> > &_dtmf);
>> > + }
>> > }
>> > }
>> > }
>> > ----8<----8<----8<----8<----8<----8<----8<----
>> >
>> > Can someone point me in the "right" direction
>> > instead? Do I need to do this at the OpenZAP/DAHDI
>> > level by disabling some kind of DTMF detection
>> > like was done for the Sangoma driver?
>> >
>> > Any and all pointers appreciated.
>> >
>> > Cheers,
>> > -Slim
>> >
>> > [1] [Freeswitch-dev] FXS bridged on FXO ports and DTMF
>> >
>>
>> http://www.mail-archive.com/freeswitch-dev@lists.freeswitch.org/msg02830.htm
>> > l
>> >
>> > [Freeswitch-dev] Problem with sending
>> > DTMF on FXS port bridged to an FXO port
>> >
>>
>> http://lists.freeswitch.org/pipermail/freeswitch-dev/2010-April/003607.html
>> >
>> >
>> > ----8<----8<----8<----8<----8<----8<----8<----
>> > [root at localhost freeswitch]# lsdahdi
>> > ### Span 1: XBUS-00/XPD-00 "Xorcom XPD #00/00: FXS" (MASTER)
>> > 1 FXS FXOKS
>> > 2 FXS FXOKS
>> > 3 FXS FXOKS
>> > 4 FXS FXOKS
>> > 5 FXS FXOKS
>> > 6 FXS FXOKS
>> > 7 FXS FXOKS
>> > 8 FXS FXOKS
>> > 9 Output FXOKS
>> > 10 Output FXOKS
>> > 11 Input FXOKS
>> > 12 Input FXOKS
>> > 13 Input FXOKS
>> > 14 Input FXOKS
>> > ### Span 2: XBUS-00/XPD-10 "Xorcom XPD #00/10: FXS"
>> > 15 FXS FXOKS
>> > 16 FXS FXOKS
>> > 17 FXS FXOKS
>> > 18 FXS FXOKS
>> > 19 FXS FXOKS
>> > 20 FXS FXOKS
>> > 21 FXS FXOKS
>> > 22 FXS FXOKS
>> > ### Span 3: XBUS-00/XPD-20 "Xorcom XPD #00/20: FXO"
>> > 23 FXO FXSKS RED
>> > 24 FXO FXSKS RED
>> > 25 FXO FXSKS RED
>> > 26 FXO FXSKS RED
>> > 27 FXO FXSKS RED
>> > 28 FXO FXSKS RED
>> > 29 FXO FXSKS RED
>> > 30 FXO FXSKS RED
>> > ### Span 4: XBUS-00/XPD-30 "Xorcom XPD #00/30: FXO"
>> > 31 FXO FXSKS RED
>> > 32 FXO FXSKS RED
>> > 33 FXO FXSKS RED
>> > 34 FXO FXSKS RED
>> > 35 FXO FXSKS RED
>> > 36 FXO FXSKS RED
>> > 37 FXO FXSKS RED
>> > 38 FXO FXSKS RED
>> > ----8<----8<----8<----8<----8<----8<----8<----
>> >
>> >
>> > Cheers,
>> > -Slim
>> > --
>> > Jeroen C. "Slim" van Gelderen
>> > Olympic Sports Data Services
>> > Email: jeroeng at thegreek.com
>> > Phone: +1 876 953 6182 x128
>> >
>> >
>> >
>> > _______________________________________________
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>
>
>
> --
> Anthony Minessale II
>
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