Date: Thu, 22 Feb 2007 15:32:04 +0100 From: Hans Petter Selasky <hselasky@c2i.net> To: Manfred Usselmann <manfred.usselmann@hp.com> Cc: freebsd-isdn@freebsd.org Subject: Re: I4B - buildkernel problem + news Message-ID: <200702221532.04632.hselasky@c2i.net> In-Reply-To: <20070222141539.0dd7ebe1.manfred.usselmann@hp.com> References: <20070222141539.0dd7ebe1.manfred.usselmann@hp.com>
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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
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