[Asterisk-Dev] A few driver ideas...

kpj at junghanns.net kpj at junghanns.net
Thu Jan 5 06:36:02 MST 2006


> A few idea's for drivers have been bouncing around in my brain, and I'd
> be interested in some feedback from the asterisk dev community...
>
> 1. zaptel wrapper for mISDN. Would this add any value to anyone? I've
> had a look around in the code for both drivers and it doesn't seem too
> impossible...

What should that look like and what should it do? mISDN handles the
complete protocol stack in the kernel but zaptel is just a stupid layer 1
device...

>
> 1a. A hypothetical question. ISDN adapter A has a perfectly functional
> mISDN (and therefore CAPI) driver available for it. ISDN adapter B has a
> perfectly functional zaptel driver available for it. Both adapters are
> reasonably priced and are functionally identical. For use under
> Asterisk, which would you prefer?

Well, zaptel ISDN drivers (as in BRIstuff) have the advantage of
delivering a timing source to asterisk. But they also reduce latency a lot
when you are bridging from an ISDN BRI card to another zaptel device (may
that be a PRI card or some FXS/FXO thingies...) because it is bridged
inside the kernel. Also debugging signalling problems in userspace is much
quicker than in kernelspace.
An additional benefit would be that you get layer 1,2,3 certified (TR3,
TRB3-A1) drivers (and protocol stack) with our zaptel approach.

>
> 2. TDMoE driver for existing ATA's (eg sipura/linksys). At a guess this
> would involve either getting Linux to run and writing a driver for any
> 'foreign' hardware... including the F[SX]O ports, or some insane black
> magic in wedging a driver into the existing O/S. Unless someone has
> Linux already running on one (I've looked and can't see any evidence of
> it having been done), then this one probably goes in the 'too hard'
> bucket. Maybe TDMoE doesn't really make sense when you are talking about
> one channel...
>
> 3. zaptel driver for the 'netjet' PCI BRI adapter (one of the few
> available in Australia, and by far the cheapest). There is an mISDN/CAPI
> driver for it now, but it is a bit unreliable for me at the moment.
> Maybe my time would be better spent fixing bugs in that...

Can you tell me which chipset they are using? I already have some
winbondish card laying on my desk that is waiting for a zaptel driver
(unfortunately it only supports TE mode but the chipset is suitable for a
good zaptel driver compared to the HFC-S PCI A chipset).

>
> James
> _______________________________________________

best regards

Klaus
--
Klaus-Peter Junghanns






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