[Serusers] Grandstream HT486 and FAX

[Darren Nay]

Yes, G711 (clear channel) is the only voice codec which you can use to send
a FAX.  The G729 codec compresses the audio stream by removing all inaudible
frequencies, which FAX machines use, and so a FAX over G729 will always
fail.

Darren Nay

> -----Original Message-----
> From: Ronald Ramos [mailto:ron at silverbackasp.com]
> Sent: Friday, October 29, 2004 9:03 AM
> To: serusers at lists.iptel.org
> Cc: asterisk-users at lists.digium.com
> Subject: [Serusers] Grandstream HT486 and FAX
> 
> 
> 
> Hi All,
> 
> I was trying to test to send a fax to an international number.
> Here's the setup:
> 
> FAX --> HT486 --> SIP PROXY --> GATEWAY --> PSTN --> FAX
> 
> Unfortunately I haven't been able to do it, I read somewhere that fax uses
> G711  only, is this true? because our gateway provider uses only G729.
> does
> this mean I can't send fax via that gateway, because of the codec?
> 
> So can i do this then,
> 
> FAX --> HT486 --> SIP PROXY --> HT486 --> FAX
> 
> i'll use G711 on both HT486.
> 
> Hope anyone can help me. Thanks in advanced.
> 
> Regards,
> Ron
> 
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