[Asterisk-Users] Re: Best drivers for HFC-S ISDN cards

[Stefan Tichy]

On Mon, Sep 26, 2005 at 02:23:04PM +0100, Chris Bagnall wrote:
> It seems that HFC-S cards can be connected with asterisk in a few different
> ways - isdn4linux, mISDN, chan_capi or zaphfc.

mISDN (kernel modules and user lib) is used by chan_misdn and
chan_capi. vISDN might be another option.


> I've tried isdn4linux (severe
> echo, reproducable on every inbound call) and zaphfc (intermittent echo,
> disappears within about 30 secs of the call starting).

There are some "Audio Quality Tuning Options" for zap channels.


> What's the recommended way to hook up these ISDN cards? Is switching to capi
> or mISDN likely to remove the echo problem completely, or is this one of
> those things one has to accept?

chan_misdn, chan_capi (echosquelch) and vISDN include a very basic
echo cancellation or non echo cancellation. IMHO bristuff is the best
(least worse) choice. chan_modem/isdn4linux will cause additional
delay and will itensify the echo problem.


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-- 
Stefan Tichy   <asterisk at pi4tel.de>