Summary:ASTERISK-07212: [patch] [post 1.4] Add support for Visdn Drivers and better support for Euro ISDN
Reporter:Rehan Khan (rasker)Labels:
Date Opened:2006-06-21 03:54:29Date Closed:2011-06-07 14:02:57
Versions:Frequency of
Environment:Attachments:( 0) visdn-devel-20060617.tar.bz2
Description:VISDN is a driver and channel driver for HFC based ISDN cards and has achieved approval for use on Euro ISDN lines (at least in Italy). It is in beta at the moment but works in the UK as well.


To use vISDN some patches need to be applied to the asterisk source code for the chan_visdn.so to correctly talk with the hardware driver. Please see the attached driver archive. The .diff files are in the samples directory.


I have applied the patches to both the general release and the latest 1.2 release. I have not found that it affects other parts of Asterisk but my experience here is limited.

Could these patches be applied to asterisk.

Please excuse any deficiencies or errors in this report. It is my first bug report ever. I would be happy to try and get any other information required.

Comments:By: Joshua C. Colp (jcolp) 2006-06-21 11:35:40

We'll look at this after we have a 1.4 beta out, and I really don't know for the licensing... but as normal you do need a disclaimer on file before we can consider putting it in. Thanks!

By: Rehan Khan (rasker) 2006-06-21 14:16:08

Thank you. The code is not mine! I am submitting on behalf of some 'users' on the visdn mailing list and especially for rpm'ed distro users (e.g. Trixbox distro) where the asterisk source is not included on the distro just the binaries. The file attached is the driver download off the visdn.org website. The .diff files are included in the samples directory and are changes to the asterisk code to support visdn driver communication between asterisk and the driver. I will ask the question regarding the licensing to the developer and he can maybe pop in a disclaimer or something. The visdn.org website does not really talk much about licensing issues but I believe the driver source code is released under the GPL.

However I have faxed a disclaimer in anyway but I guess this just applies to me.

Other HFC chipset drivers seem sucky in comparison even though the driver is not fully developed.

Rehan Khan

By: Serge Vecher (serge-v) 2006-06-21 14:36:58

rasker: as Asterisk already supports ISDN connectivity through chan_mISDN, there are questions as to what would be the value of adding support for vISDN. The best place for this discussion to take is on the asterisk-dev mailing list, where it can get exposure both from the core development team and development community at large. Pending, I am suspending this issue at this time.

By: Michael Jerris (mikej) 2006-06-21 14:37:34

for this to get in, we are going to need a disclaimer for all the code that would go into asterisk from the copywrite holder.  The driver itself would not be need to be disclaimed, and as I would see it would not reside in the distribution.  Can you find out if this is even possible to get disclaimed, if not, there is little that could be done to get this in tree.

By: Rehan Khan (rasker) 2006-06-21 16:05:49

Thanks for taking the time to respond.

I am using a Beronet 4 port passive ISDN BRI card. Trixbox uses Centos 4.3(=Redhat 4 Enterprise=kernel 2.6.9 with back ported patches from later kernels). A major issue with the mISDN driver was that the Centos distro has profiling switched on which caused (I believe and this was also indicated by Beronet support) high cpu loads and the machine to become unresponsive for periods of time when an ISDN channel was being used. With profiling switched off (after a kernel update and re-compile) the driver did work much better however I could not make outgoing calls (maybe a problem with my dial plan!). Anyway it was a painful experience. Also the kernel update, although relatively simple to do (was my first) maybe out of the reach of many new users who just want an easy to install and configure PBX (=Trixbox distro). vISDN will support kernels all the way back to 6.2.8 with profiling enabled. (tested and works). The value I guess is that it will work on a more diversified Linux OS than mISDN (less stringent requirements) and is more generic (any HFC card). Also there is much more 'feedback' from the driver (to see if it is running ok you can just type ifconfig and you can see a list of your ISDN interfaces, it supports ISDN E channel so you can actually capture the ISDN signalling with a packet sniffer). I guess a big limitation is that it does not fully support echo cancelling on the card yet (not an issue for passive card users).

The developer is hard at work on a V1.0 release so a post 1.4 asterisk timeframe is realistic.

The benefit of including the changes in the released asterisk version would be that the vISDN driver would be more accessible to people who use Asterisk distros like Trixbox (which are RPM based) and want to keep thier machines updated using existing mechanisms (Yum). The biggest advantage of using the Trixbox Distro is that configuration and updates are simplified as the OS and asterisk get updated by using Yum. Asterisk thus becomes accessible to a larger group of people  - those who may not want to delve into the innards of Linux just to make a phone call.

Many small businesses in the UK and also Europe use ISDN BRI's for their telco connectivity. These are small installations (6-8 channels) and a card and driver that supports TE mode without hardware echo cancellation is sufficient.

vISDN really worked for me where other drivers failed.

I will take this to the development mail list as you kindly suggested. I have a post on the vISDN mail list asking the developer to clarify the licensing situation so hopefully I can get back to you on this in the near future (a signed disclaimer perhaps would be sufficient?)

I guess you can push this back to suspended.
Many thanks.


By: Rehan Khan (rasker) 2006-06-21 23:17:44

The drivers and all other code are licensed under a GPL v2 license. This is from the readme's in the in the attached file.

By: Olle Johansson (oej) 2006-06-22 02:09:54

rasker: Please read the bug guidelines and what we've said about disclaimers. Even though Asterisk is released under GPL, new code has to be disclaimed to Digium in order to allow Digium to publish Asterisk under several licenses, including the GPL version. This is very similar to MySQL, which also uses dual licensing.

As said before, the original coders, the copyright holders, need to disclaim their copyright. Read more about it in the bug guidelines, a URL is to be found on the home page of the bug tracker. If you want to discuss this, use the #asterisk-dev channel on IRC or the asterisk-dev mailing list.

Thank you for wanting to contribute to Asterisk!