[Freeswitch-users] Ademco signaling with mod_spandsp

[Steve Underwood]

On 08/19/2013 11:54 AM, Moises Silva wrote:
> On Sun, Aug 18, 2013 at 8:18 PM, Brian Foster <bdfoster at davri.com 
> <mailto:bdfoster at davri.com>> wrote:
>
>     It's probably easier to write something in LUA to handle this.
>     Seems pretty straightforward looking at the standard. Might be
>     wrong though.
>
> Although not rocket-science, I believe you might be underestimating it 
> a bit :-)
>
> I have not looked at the standard and have no experience at all with 
> the protocol, but the code is in spandsp for a reason, there are some 
> per-sample digital audio calculations, tone/silence detection etc, 
> with strict rules/timing that most likely you won't be able to do from 
> LUA.
>
> See libs/spandsp/src/ademco_contactid.c comments
>
> I believe the right approach is to write a mod_ademco wrapper that 
> exposes the functionality to the dialplan (either through dialplan 
> applications or functions), then you can write LUA scripts :-)
>
> Moy
Moises is right. You can get close to an Ademco receiver without special 
code, but you won't really meet the detailed timing of the spec without 
doing a proper job. You won't get anywhere trying to make a decent 
Ademco sender without specialised DSP code. spandsp implements both 
sides properly. Why not use it?

Steve