[Asterisk-Users] Asterisk - Spandsp: fax header

[Steve Underwood]

Jean-Yves Avenard wrote:

> Hi Peter
> On 18/05/2005, at 10:05 PM, Steve Underwood wrote:
>
>> It is only there because the sending machine put it there in the 
>> image. Spandsp is not different from how any FAX machine I have ever 
>> used behaves. As well as sending the 20 digit number as text, the 
>> sending machine puts in the header.
>>
>>
>
> This is not what I'm referring to... I know what is being put by the 
> remote fax !
>
> On my Brother's fax machine (MFC-8820D) today, I've received 3 faxes: 
> all of them at the top showed the caller Fax identity.
> I received 2 faxes on Asterisk with spandsp, one from the same sender 
> as earlier on the brother: there's nothing at the top.
>
> I wouldn't ask if it was obvious the data was inside the image, give 
> me some credits for God's sake !

What you are describing is something I have never seen a FAX machine do.

> Typically, when somebody is sending a fax on the Brother unit, once 
> the connection has been established the identity of the fax caller is 
> then displayed on the Brother's LCD (and this has nothing to do with 
> PSTN CallerID), what is displayed on the LCD will be printed at the 
> top of each pages. This is this behavior I'm trying to reproduce with 
> Asterisk/Spandsp.

So you get the calling machine's number shown twice at the top of each 
page? Once in this extra header, and once in the normal header sent as 
part of the image? Weird. FAX machines don't normally do that. Does this 
extra header overlay a part of the page, or does it make the page one 
line longer?

Spandsp puts the calling machine's number in one of the tag fields in 
the TIFF headers. It puts several things in those tags - the name of the 
software which generated the file (spandsp), the hostname of the 
receiving computer, the far machine's ident, the far machine's maker and 
model (if they can be identified). Programs like tiffdump will show that 
information. Some image viewers also allow you to see it (don't ask me 
which ones off hand).

Regards,
Steve