[asterisk-dev] How to pass a parameter to the DAHDI kernel driver ?

Kevin P. Fleming kpfleming at digium.com
Wed Sep 14 16:48:42 CDT 2011

On 09/14/2011 03:22 PM, Pavel Troller wrote:

>    Of course, to use it, you need a hardware capable of sending the pulses to
> the phones. In my case, it's using a kind of "channel bank" or "E1
> multiplexer", utilizing a standard Asterisk E1 card with a special type of
> DAHDI signalling on it (a variant of european CAS with DTMF or pulse dialling),
> which I've written formerly as a closed project. The multiplexer contains FXS
> cards, which are able to generate 16 kHz or polarity reversal pulses according
> to their strapping. I don't know, whether any Digium or other native Asterisk
> FXS cards can generate 16kHz, but they probably can generate polarity reversal
> pulses. However, I don't have any of these cards, so implementation of the
> lowest layer of sending the pulses to the hardware for such a card has to be
> done by someone else.

Yes, all the FXS cards/modules that I am aware of can generate polarity 
reversals; they are necessary for some signaling modes. I have no clue 
whether the devices used on those modules are capable of generating a 
16kHz tone; I suspect not.

>    I can submit a patch, residing in chan_dahdi.c, sig_analog.c, dahdi-base.c
> and corresponding include files, but it's based on 1.8 branch. Currently
> I don't have a running 1.10/trunk installation, so I cannot adapt the patch
> for it. Is anybody interested in adapting this change to the Asterisk trunk ?

Kevin P. Fleming
Digium, Inc. | Director of Software Technologies
Jabber: kfleming at digium.com | SIP: kpfleming at digium.com | Skype: kpfleming
445 Jan Davis Drive NW - Huntsville, AL 35806 - USA
Check us out at www.digium.com & www.asterisk.org

More information about the asterisk-dev mailing list