New version of ISDN4BSD and CHAN_CAPI available

[Hans Petter Selasky]

Hi,


A new version of ISDN4BSD and chan_capi for Asterisk is available. Please see:


http://www.turbocat.net/~hselasky/isdn4bsd

And:

http://www.turbocat.net/~hselasky/capi4pbx


Some news:

There will be support for HFC-4S/8S in not very long. I am currently awaiting 
hardware to do some testing. The driver is already in the sources.

Many people are starting to use Asterisk and I4B in NT-mode, for their main 
home PBX. This works pretty well. The only problem so far is when bridging 
modems and faxes, which do not always succeed. To make such devices work 
better, I4B now supports line interconnect through /dev/capi20. Currently 
only HFC-E1 and HFC-4S/8S based cards will have support for that. Line 
interconnect must be configured using "isdnconfig" before it works. The big 
problem is called echo cancelling. To save money, telephone manufactureres 
often let the network side do this part, in other words I4B. Doing echo 
cancelling in software is a very CPU intensive task, so instead of performing 
echo cancelling, "chan_capi" can perform echo suppression, which is easier 
and sounds perceptually the same. Currenly my version of "chan_capi" has a 
brand new echo suppressor, that even has a white noise generator for your 
comfort. The echo suppressor allows faxes to pass through, but not duplex 
modems. In NT-mode, I4B seems to be stable. That means it should not crash 
the connected PBX, due to software bugs and memory leaks.

Have fun.

--HPS