I'd like to know if IAXmodem already supports fax speed transmission at 33.6kbps.
I've found from this page (https://www.voip-info.org/asterisk-iaxmodem/) that:
"Iaxmodem uses the spandsp library. So currently its modulation protocol support covers V.27ter, V.29 and V.17. V.34 (Super G3) support is not available, and won’t become available in the near future for patent reasons..." Which means that fax speeds from 2400 bps to 14400 bps are supported. However, I dont know how long has been since those "patent reasons", and if IAXmodem already works at higher speeds, with V.34.
Thanks
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There is some V.34 support in SpanDSP. I don't think that it's patent-encumbered any longer. However, the last time that I tested V.34 in SpanDSP I couldn't get it working well against other V.34 (SuperG3) fax modems. (Maybe I didn't test correctly?) So, I didn't bother getting into the necessary developments for the required T.31 interfaces. (Once the V.34 modems are working reliably in SpanDSP then IAXmodem will still need the associated T.31 interfaces developed - also in SpanDSP.)
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
Hi,
I'd like to know if IAXmodem already supports fax speed transmission at 33.6kbps.
I've found from this page (https://www.voip-info.org/asterisk-iaxmodem/) that:
"Iaxmodem uses the spandsp library. So currently its modulation protocol support covers V.27ter, V.29 and V.17. V.34 (Super G3) support is not available, and won’t become available in the near future for patent reasons..." Which means that fax speeds from 2400 bps to 14400 bps are supported. However, I dont know how long has been since those "patent reasons", and if IAXmodem already works at higher speeds, with V.34.
Thanks
There is some V.34 support in SpanDSP. I don't think that it's patent-encumbered any longer. However, the last time that I tested V.34 in SpanDSP I couldn't get it working well against other V.34 (SuperG3) fax modems. (Maybe I didn't test correctly?) So, I didn't bother getting into the necessary developments for the required T.31 interfaces. (Once the V.34 modems are working reliably in SpanDSP then IAXmodem will still need the associated T.31 interfaces developed - also in SpanDSP.)