[Asterisk-Users] T.38 fax summary

[Martijn van Oosterhout]

On Sun, Feb 27, 2005 at 09:10:48AM -0800, Lee Howard wrote:
> Fax cannot handle a one-second delay.  As Steve mentions in the 
> article, per-spec fax has some timings (particularly silence in 
> direction "switching") set at 75 ms +/- 20 ms.  So if the delay gets 
> much larger than 75 ms, then there's likely to be trouble.  Now, some 
> fax machines may tolerate larger delays, but that tolerance is beyond 
> the spec, and thus should not be used as a gauge.

Something's not right here. In 75ms light has just made it from here to
the other side of the world. Even a PSTN network will provide a longer
delay than that calling across the world. And the time to get a
response back will be around twice that, which is well beyond that
tolerated range.

If you're saying there is a limit to the round-trip-time then within
the fax specification is a predefined maximum physical distance you can
send faxes.

Faxing across the world does work so there is something else going
here...
-- 
Martijn van Oosterhout
Ecomtel Pty Ltd