10 Apr
2012
10 Apr
'12
4:17 p.m.
On 10/04/2012 22:03, Brent Hilpert wrote:
On 2012 Apr 10, at 11:31 AM, Dave Wade wrote:
Almost, I believe there are/were three standards that appertain to a
PAD, X.3 describes how the terminal interacts, and X.28 describes what
the user does and X.29 which describes how the host behaves. So these
were call "Triple X standards". It was Janet so they just had to be
different. The PAD had extensions to X28 and they had their own extra
"Standard", TS29, which was X.29 over Yellow Book Transport(YBTS). From
what I recall YBTS does not map well to an OSI transport service but it
did allow traffic to be routed across multiple disperate X.25 networks.
So in the UK the Post Office (later BT) X.25 Packet PSS network had
addresses starting "2342". As you couldn't get an official allocation
for a private X.25 network Janet used the range starting "0000". If you
wanted to route a connection from a PSS link to a Janet site with no PSS
addresses you had to use a relay of some kind. YBTS added an extra layer
and allowed through routing.
I think I still have the BT manual which lists the numbers and addresses
of its dial-up notes....
Dave G4UGM
Practical X-25 networking Alan Buttle (and others) ISBN 0-9508677-0-5
may be informative on X.25....
... and a search on Wikipedia reveals some of the standards are now
freely available from the ITU... http://en.wikipedia.org/wiki/X.25 and
links at the bottom
On 10/04/2012 19:07, Sam Onella wrote:
FWIM and IIRC, X.29 was the standard that describes how an X.25 async
terminal PAD is to operate. (It is conceivable JANET had their own
standard for such, but I expect it is more probable they were
following the 'official' standard.)
Just googling around, so apologies if I'm way
off, but is it like
this
http://benjeapes.blogspot.com/2010/06/back-when-pad-didnt-even-mean-pad.html
? Is it a serial sniffer? If so and assuming you know which serial
input and standard it's using you could probably either hook up
another serial sniffer/analyzer to it and see what it's doing or a
standard terminal would likely spit something out once you figure
out the proper communication settings. Given no clue if it's DTE or
DCE.
Its a X25 Packet/Assembler/Dissasembler. It allows ordinary Async
Terminals to be connected to an X.25 network. In the UK all
Universities had such networks under the umbrella of JANET. Some at
Janet probably has a manual. I have forgotten almost every thing I
know about them. I have asked one of my former colleagues if he has
any info.