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

[kpj at junghanns.net]

>> > 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...
>
> Ah. That makes some sense. So where is the protocol stack handled if
> zaptel is doing layer 1? Userspace?

Yes, libpri is handling the signalling in userspace. It has the big
advantage that you can make modifications to the stack without risking to
blow up your whole kernel.

It also increases portability. On what systems does mISDN run? Linux? ;-)
I am currently preparing to port BRIstuff to OS-X.


>
>> > 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.
>
> So if you have some existing zaptel stuff, a zaptel driver based card
> would definitely be the better option?
>
>> > 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).
>
> It's supported by the hisax driver and users the 'Tigerjet320' PCI
> chipset and a Siemens ISAC. If that doesn't help I can probably find out
> more...

I am not familiar with the Tigerjet chipset. Can you get a 1khz timer out
of it? If yes, a zaptel driver is possible.


>
> James

Klaus