[asterisk-users] Digium Fax Driver

[Steve Underwood]

sean darcy wrote:
> Tzafrir Cohen wrote:
>   
>> On Sun, Jun 07, 2009 at 10:15:42PM -0500, Tilghman Lesher wrote:
>>
>>     
>>> IAXmodem is a completely different ball of wax, and I think you would agree
>>> that if the builtin FAX support in spandsp provided excellent support, there
>>> never would have been a reason for IAXmodem to be developed.
>>>       
>> Reminder: SpanDSP was originally GPL. Steve Underwood wrote rx_fax.c and
>> tx_fax.c that were basically thin wrappers for it. They were not so easy
>> to use because:
>>
>> 1. They were out of tree to start with (which made life much more
>>    difficult. Certainly before 1.4).
>> 2. The API and ABI of SpanDSP kept changing, and you had to know the
>>    right version to use.
>> 3. They weren't much well-behaving Asterisk apps (e.g.: used their own
>>    log file) and generally got very little maintinance (also due to
>>    (2)).
>>
>> There was much resistance to even adding those apps to asterisk-addons.
>> I guess that merely (2) would have made them a support burden. IAXmodem
>> avoided the issue by using its own copy of SpanDSP.
>>
>> With the release of SpanDSP 0.0.5 things started changing:
>>
>> A. The license was changed to LGPL for the library itself. This allowed
>>    using it is Asterisk and FreeSwitch.
>> B. Finally some attention to stable API and ABI.
>>
>> An app_fax.c was written initially in Asterisk-Addons only about at this
>> stage, with an eye on T.38 integration. Shortly after it was moved to
>> Asterisk itself. 
>>
>> This was when Asterisk 1.6.0 was at release stages, IIRC. At the time
>> IAXmodem was well-mature. So what you wrote should probably be rephrased
>> as:
>>
>>  If the builtin FAX support in *Asterisk* provided excellent support, there
>>  never would have been a reason for IAXmodem to be developed.
>>
>> (But still see Lee Howard's comment in the other followup).
>>
>>     
>
> OK, back to the original question: Do they provide the same service? I 
> get the point that the Digium Fax may (or may not) provide V.34. 
> Anything else?
>   
I think it gives you JBIG compression, which spandsp can't because of 
patents. It doesn't give you V.34, which is the really interesting thing 
Digium could have offered. That's about it.

Steve