dave@utcsrgv.UUCP (Dave Sherman) (03/07/84)
We have installed a MICOM X.25 PAD at the Law Society to hook ourselves
up to Datapac and a Toronto law firm network, as a means of enabling access
to our CAI from law firms.
I'm having an awful problem trying to figure out how one changes
X.25 parameters on a remote PAD from the host machine. I know it
can be done. I think it's X.29 I'm looking for, but no-one I talk
to (including the PAD dealer and manufacturer) seems to know just how.
The Micom manual indicates that the PAD can do X.29, but doesn't tell
me how.
Changing parameters on the PAD you're hooked up to is easy.
"<ctrl-P>set 2:1", for example, turns echoing on. Now how do I
have UNIX do it so the user doesn't have to be told about it??
Thanks for any illumination on this confusing subject.
Dave Sherman
The Law Society of Upper Canada (utcsrgv!lsuc!dave)
Toronto
(416) 947-3466
--
{allegra,cornell,decvax,ihnp4,linus,utzoo}!utcsrgv!davejulian@deepthot.UUCP (Julian Davies) (03/09/84)
Yes, the remote PAD can be changed with X.29 procedures. This is
impossible unless you are handling the full X.25 service (Datapac-3000
in Canada). You have to be able to send and receive data packets with
the Q (Qualifier) bit set.
In theory, one PAD can read and control another, when both ends of
the VC are on PADs, but there is no protocol defined for a user of
an asynchronous terminal to read or set PAD parameters at the *far*
end, only for one's own local PAD (X.28).
X.29 defines uses of the call user information at VC setup, and also
the user data packets with Q bit set. The latter packets have the
data field in the following format (Fig. 2/X.29 (1980))
Octet 1 0 0 0 0 | msg code
2 parameter reference
3 parameter value
4 parameter reference -- if more than one
....
Message code: 0010 - Set
0100 - Read
0110 - Set and read
0000 - parameter indication
In PAD read messages, the 'value' fields are set zero -- the
indication packet will come back with values filled in.