I4B - buildkernel problem + news

[Hans Petter Selasky]

Hi,

After you do a CVSUP you have to re-install I4B. Did you follow these 
instructions:

If one has got Subversion installed, the latest sources can easily be obtained 
by running the following command: 
svn --username anonsvn --password anonsvn \
      checkout svn://svn.turbocat.net/i4b
#
# The following commands will 
# install the driver on FreeBSD:
#
cd i4b/trunk/i4b/FreeBSD.i4b
make S=../src package
make install

By the way, here is some news:

At the present moment I am working on an integer based Fast Fourier echo 
canceller. This means that data is processed in blocks instead of sample by 
sample. The main advantage is that the number of multiplications are reduced 
significantly. Before I would spend at least 256 multiplications per sample. 
Now I spend approximately (40960 / 512) = 80 multiplications per sample for a 
512-tap FIR filter! This new echo canceller is not yet in the SVN repo, but 
if you are interested in echo cancelling and want to help then feel free to 
contact me.

Else I have got messages back from several people using Asterisk [and OpenPBX] 
successfully with my new I4B and "chan_capi". To use my new "chan_capi" with 
OpenPBX you need a small script that will convert ast_ into opbx_ and alike. 
This script is not yet in the SVN repo.

Also some people have decided to use my new version of I4B in their commercial 
products.

The "HFC-S USB" based ISDN USB adapters have now got support for kernel echo 
cancelling. Implementing echo cancelling posed some challenges like that you 
during certain conditions will receive more data than you transmit, and vice 
versa. Then the coefficients in the FIR filter has to be shifted up or down, 
to reflect the changes.

--HPS