[Asterisk-Users] Asterisk mangling faxes

[Steve Underwood]

Hi Darren,

Darren Nickerson wrote:

>>Steve Underwood wrote:
>>    
>>
>>Are you sure that approach is free from patent problems? I thought the
>>ECM protocol was encumbered. If not, that is good news. :-)
>>    
>>
>
>Steve,
>
>I'm not a lawyer, but I'll give this a shot ;-)
>
>Although particular vendor implementations of ECM may be proprietary, ECM is
>a standard outlined in the ITU's Recommendation T.30, so it's no more
>encumbered than a whole lot of stuff your rxfax and txfax doodads are
>already doing.
>  
>
I don't think that argument holds water. ITU recommendations are filled 
with patented things. I have only implemented FAX features from the 
original FAX standards, which are too old to still have patent problems. 
I am very cautious about adding newer stuff. I have a prototype 
implementation of V.17, but it isn't going into the distribution right 
now, as there appears to be a patent on something about the trellis 
coding (my implementation doesn't do the Viterbi decoding yet, so its 
probably clear of patent issues right now :-) ). T.30 has *many* patent 
claims on it, if you look at the ITU database of patent claims. I think 
one or more relate to ECM.

Regards,
Steve