On 05/05/2011 03:29 AM, Lee Howard wrote:
David Backeberg wrote:
On Wed, May 4, 2011 at 12:00 PM, A J Stiles
<asterisk_l...@earthshod.co.uk> wrote:
(For my part, I'm actually surprised that nobody came up with a proper
protocol for encapsulating the stream of zeros and ones that make up
a fax
transmission but rely on the precise timing inherent with a
circuit-switched
network, into something more suitable for sending over a
packet-switched
network. That would have fixed it good and proper.)
They did. It's called TCP / IP.
It allows sending PDFs, and they can even be encrypted.
Faxing is for people who haven't heard of the internet.
Nobody has said that faxing couldn't use TCP/IP... and there's no
reason why T.38 couldn't use TCP/IP. Nobody has said that faxing
couldn't use HTTP as a transport... or SSL... or any other kind of
sensible mechanism. Why in the world people try to keep faxing (data
transfer) tied-down to audio channels by putting T.38 into H.323 or
UDP/IP SIP beats me.
T.38 is defined to work over TCP/IP (although not TLS for some reason),
but its rarely used. It can only really work between 2 T.38 boxes
directly connected to the data network. To interwork with analogue FAX
machines you need to maintain fairly tight timing, and that means
sticking with UDP, as it does with all the other streaming stuff we do
over UDP.
Steve
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