[asterisk-dev] Support for Dialogic DM3 cards

Gilmore, Gerry gerry.gilmore at intel.com
Mon Mar 27 09:23:20 MST 2006


While Steve is absolutely correct that the older Dialogic cards were
only half-duplex, the newer "JCT" series of cards - and all of the DM3
series cards - do support full-duplex audio streaming through a single
DSP, so they can fit into the Asterisk architecture quite nicely - once
you tune those buffer sizes, which we are doing in our channel driver.
:-)

More broadly, though, to the bigger question of DSP vs HMP (Host Media
Processing: Intel-speak for audio processing through the host CPU),
obviously there are many situations where HMP is the ticket. Certainly
Steve's HMP routines in Asterisk have shown the power of this technology
and we at Intel sell our own HMP. However, there are some situations
where - for right now, anyway - onboard DSP support, especially when
coupled with an onboard T1/E1 interface for advanced call control, can
be more efficient, especially in higher call volumes. 

I think the fact that Digium themselves seem to be moving towards more
onboard DSP-type processing in their products bears out this fact much
more than anything that I could say, anyway.

Finally, for those of you who met Dwayne (the Intel programmer leading
the chan-dialogic driver effort) or myself at VON, then you already know
that we are driving towards releasing the channel driver with the next
release of Asterisk Business Edition, due RSN. As an earlier poster
noted, for several reasons, our channel driver is available only in
Asterisk Business Edition. As an old-time open source believer, it pains
me personally for this to be the case, but at this point it is a matter
of having an ABE-only channel driver or no channel driver.

Gerry
   

There are 10 kinds of people in the world, those who understand binary
and those who don't.
 
Gerry Gilmore
Field Applications Engineer
Intel Corporation
(http://www.intel.com)
 

-----Original Message-----
From: asterisk-dev-bounces at lists.digium.com
[mailto:asterisk-dev-bounces at lists.digium.com] On Behalf Of Steve
Underwood
Sent: Saturday, March 25, 2006 10:09 AM
To: Asterisk Developers Mailing List
Subject: Re: [asterisk-dev] Support for Dialogic DM3 cards

Wai Wu wrote:

>---- i could comment on 'whats *loose* around here' but, there is no
reason too.
>
>---- either you believe in asterisk and  what it can do for you.  (or
you don't)
>
>---- if you are the latter, i'd suggest you leave before others sense
your
>---- lack of commitment.
>
>---- god forbid, you are a dialogic mole <G>.
>
>
>Gee, you guys sound like a cult. LoL. 
>  
>
I think that guy sounds more like a cretin.

>Seriously, I am looking for ways to better integrate Dialogic/Aculab
cards with Asterisk. The way it is done right now is very wasteful on
the hardware (two speech resources per channel) when routing calls from
PSTN to, say, IAX trunks. When I know more about the * source code,
there might opportunity for a solution to this. 
>  
>
The problem lies with the hardware, at least for Dialogic. There are
Aculab drivers for *, but I don't know much about the Aculab cards. I do
know quite a lot about the Dialogic cards, and they are very limiting.
Most of the voice resources, and all the older one, are half-duplex. You
can only do VoIP calls with a pairs of these resources. Even then, the
performance sucks. Dialogic use huge amounts of buffering. This is great
for IVR applications, as it makes the software timing very relaxed. For
VoIP it makes the latency awful. There is a good reason why Dialogic
built a completely separate line of cards for VoIP - the IVR + H.100 bus
voice oriented cards really don't cut it.

Regards,
Steve


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