Re: mISDN2 supported hardware

On Sun, Dec 02, 2012 at 04:13:00PM +0100, Patrick Lists wrote:
> On 12/02/2012 02:31 PM, Jacek Konieczny wrote:
> > 1. it is included in the upstream kernel
> 
> While that may be nice the mISDNv2 drivers can also be built in a 
> separate tree outside of the kernel. I would use the most stable and 
> suitable kernel I can find and not the one that is convenient because it 
> has the drivers included. Customers tend to expect (demand) that a PBX 
> be very reliable so a boring reliable proven kernel is what I would choose.

We choose kernel version for many other features which we rely on.

I would prefer a boring reliable proven drivers which can be compiled
for any reasonably modern vanilla Linux kernel (official stable
release).

I have not had any bigger problems with current stable kernel. What
usually causes problems are external drivers and patches.

> > 2. hardware information is discoverable from userspace (Zaptel/DAHDi
> > drivers required hardware settings known and configured before the
> > modules have been loaded).
> 
> Maybe I misunderstood but I always had to configure both DAHDI (zaptel 
> is EOL), Sangoma and mISDN so don't see the advantage.

With mISDN the drivers for the right hardware are loaded automatically.
I can change the hardware settings (NT/TE port if that is configurable),
but I don't have to decide what module load and with what options.

This way I may have a system which can be extended by just adding a
supported card with no need to configure it for the hardware – just for
the ISDN line. And this is much easier with mISDN/LCR than it was with
Zaptel and early DAHDI.

> > 3. easy, mostly hardware-independent, configuration (vendor-specific
> > drivers and many DADHDi drivers need special coding for specific device)
> 
> Not to be dense but aren't drivers hardware-dependent?

Yes. Drivers are, but they should provide hardware independent API.

If card A provides different API then card B, then I must maintain two
different versions of code to support them both.

> Why else would 
> you need them? :-) Not sure what you mean with "special coding". If you 
> use Digium cards and DAHDI drivers then there is no need for patches. 

Right.

> Just configure, start and use. The same goes for Sangoma and mISDN.

But if I want to support three pieces of hardware and one is supported
by mISDN, the other by DADHI and the third by proprietary API (Sangoma?)
then there is much more work to handle that than there should be.

I don't have to do extra coding to have a different Ethernet card
supported. I just need the driver.

> Get an ISDN card with a Cologne HFC chip on it (I'm not sure if the XHFC 
> chips are supported yet). You can recognize the chip because it has a 
> picture of the Cologne Cathedral towers on it as can be seen here: 
> http://www.rjsystems.nl/img/ccd_hfc-s_pci_a_2bds0_251-fthr.jpg
> http://www.stedentipsvoortrips.nl/duitsland/Keulen.dom.jpg

The problem is we have tried a few of those. And it have never worked
'out of the box'. Each vendor seems to do something their way. Different
PCI-ids (not recognized by unpatched mISDN) is the least significant
problem. Even LEDs seem to be wired differently for each piece of
hardware…

> > We have been trying to use OpenVOX cards, but even their PCI-ids were
> > not included in mISDN drivers. Just adding the IDs gave only basic
> > functionality. LEDs were not working properly, and we couldn't even hope
> > for using the hardware echo cancellation modules.
> 
> Afaik the OpenVox cards use DAHDI drivers (may need patches). In the 
> past they used mISDNv1 and Bristuff. Check the download section on their 
> website where most mISDN patches/code all seem to be for mISDNv1.

Yes, but isn't mISDNv2 the current mISDN version? The API supported by
Linux kernel?
And they did provided us with one 'mISDN2' driver… which was quite
useless.

> Afaik most mISDN patches/code from OpenVox is for mISDNv1 not mISDNv2. 
> See for example: http://downloads.openvox.cn/pub/drivers/mISDN/
> These days OpenVox offers patched DAHDI drivers for their cards.

And again, I am afraid these patched DAHDI drivers are not compatible
with standard DAHDI (that was the case when we tried OpenVox Zaptel
drivers)… so it will be OpenVox or Digium, not both, unless we do extra
work to make those OpenVox drivers proper…

> > Is there any list of mISDN2 compatible hardware? Are there any devices
> > currently on the market known to work properly with mISDN2?
> 
> Afaik any card with a Cologne ISDN chip which i supported by mISDNv2. 

My experience shows it is not the case. That is why I am asking for
specific hardware models.

> Afaik Karsten (and others?) has made a ton of effort to get the mISDNv2 
> drivers included in the upstream kernel. So if you want to use those 
> mISDNv2 drivers then you need to find an mISDNv2 compatible ISDN card. 

That is what I am trying to do.

> If you want to use OpenVox cards then you need to use DAHDI.

And that is what I maybe be forced to do if I cannot find a sane mISDNv2
compatible card.

The other option is to use Berofix, which I don't like much, because it
is putting another ISDN/SIP switch inside of our ISDN/SIP switch…

> If you want to use mISDNv2 then talk to the company whose products the 
> mISDNv2 drivers were written for: Cologne Chip. Their website can be 
> found at http://www.colognechip.com/

This is a chip manufacturer, not a card manufacturer, isn't it?
I know mISDN2 probably works great with reference designs and
development boards for this chips, but I need actual 'end-user' ISDN
card product.

> Finally, you did not mention which software you will be using. If you 
> want to use FreeSWITCH then mISDNv2 based cards will probably not work 
> as last time I asked FreeSWITCH did not have mISDNv2 support.

Asterisk+LCR – this works great for us as long as the mISDNv2 drivers
behave correctly.

Greets,
        Jacek
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