Jerry Jones wrote:
Turning ECM seems to cause most of my issues with FAX. Most newer machines have this on by default. However if there is any packet loss, then when ECM tries to resend and there is additional loss, then it gets in a loop and everything just fails. Whereas with ECM off, you may have an occasional extra or missing pixel, but most users never notice, and the speed is way faster. Most complaints are solved by jsut turning ECM off. Of course this does not necesarily help mortgage companies who seem to enjoy faxing 50page legal docs....
A 50-page non-ECM fax is similar to an average 20-page ECM fax in that there are repeated sections of V.17/V.29/V.27ter modulation occuring. That high-speed data communcation is the really sensitive part about faxing and getting a mistaken carrier drop during that time is the thing that kills.
If you're saying that a 50-page legal document will frequently have troubles, then you're talking about an error ratio that most businesses of my acquaintence would simply not tolerate.
In a typical lossless audio environtment, fax speeds with ECM should be the same or better due to additional compression mechanisms that require a lossless image type. If you find that your fax speeds with ECM are frequently slower than without ECM... or if you find that ECM fails more frequently than non-ECM, then it would seem to indicate that the audio corruption that is occurring before audio gets to your fax machine is fairly severe.
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