Date: 25 February 1984 12:33-EST
From: Devon S. McCullough <DEVON>
To:   A2DEH

This is from the file SYSENG;TELSER >
And you can get details from the ARPAnet Protocols Handbook.
These work from either end.  You'll notice that some of our
favorite @-type TAC commands aren't in the protocol at all,
limiting just what MC can do to a TAC using Telnet.
Of course if you want to send a 377 as data you double it.

;NEW TELNET CONTROL CHARACTERS

NT%IAC==377	;INTERPRET FOLLOWING CHAR AS COMMAND
NT%DONT==376	;DON'T <OPTION>
NT%DO==375	;DO <OPTION>
NT%WONT==374	;WON'T <OPTION>
NT%WILL==373	;WILL <OPTION>
NT%SB==372	;SUBNEGOTIATION BEGIN <OPTION> <TEXT...> IAC SE
NT%GA==371	;GO AHEAD
NT%ERL==370	;ERASE INPUT LINE
NT%ERS==367	;ERASE INPUT CHARACTER
NT%AYT==366	;ARE YOU THERE
NT%AO==365	;ABORT OUTPUT
NT%IP==364	;INTERRUPT PROCESS
NT%BRK==363	;BREAK
NT%DMK==362	;DATA MARK
NT%NOP==361	;NOP
NT%SE==360	;SUBNEGOTIATION END

;NEW TELNET OPTIONS

OP%BIN==0	;TRANSMIT BINARY
OP%ECO==1	;ECHO
OP%SGA==3	;SUPPRESS GO AHEAD
OP%LOG==18.	;LOGOUT
OP%SUP==21.	;SUPDUP
OP%LOC==23.	;TTYLOC

Note that you can't request the SUPDUP option except at the very beginning of
the session, so once you have typed and received characters it's too late.
You could of course get a SUPDUP program for the VAX, that asks for it
as soon as it connects.  I think that TELSER blows away the code and associated
memory used to negotiate the initial connection once data starts flowing.

By the way, you may not know about SUPDUP codes 300 and 301, which are
LOGOUT and TTYLOC <ASCIZ text> although I forget which is which.  But
if you are sending SUPDUP codes over a TELNET connection I guess that
TELSER won't notice them.

Your TELSER is named nnTLNT where nn is your TTY number, so if you do
:VV DEVON to find my TTY number and then :VV nnTLNT you can see where
I'm coming from since TELSER sets it's SNAME to the net site name.

Here's some interesting locations in your TELSER you can look at from
DDT or with your own programs:

IFN .-100, .ERR THIS HAS TO BE AT 100, PWORD AND NAME LOOK AT IT
	'TERMID		;MAGIC IDENTIFIER
TERMID:	BLOCK 8		;IF NON-ZERO, AN ASCIZ TERMINAL NAME
HSTNAM:	BLOCK 8		;IF NON-ZERO, THE NAME OF THE HOST IN ASCIZ
TIPNUM:	0		;IF NON-ZERO, PORT NUMBER ON TIP
FHOST:	0		;FOREIGN HOST CONNECTED TO
HSTSIX:	0		;SIXBIT NAME OF HOST
FUNAME:	0		;SIXBIT NAME OF USER AT FOREIGN SITE
HSTAT:	0		;FOREIGN HOST STATUS (SERVER, USER, TIP)
 ;END OF STUFF LOOKED AT BY PWORD AND NAME.
 ;THESE NEXT THREE LOOKED AT BY LMODEM, OR ANYONE ELSE WHO WANTS
 ;TO SEE IF WE THINK WE'RE IN BINARY MODE.
 ;THE VARIABLE IS NEEDED ANYWAY TO PREVENT INFINITE ACK LOOPS
 ;UNDER SOME CONDITIONS.
IFN .-126, .ERR BINARY MODE INFO NOT WHERE EXPECTED
	'BINARY
TRBINF:	0		;-1 RECEIVED IAC DO TRNBIN
RCBINF:	0		;-1 RECEIVED IAC WILL TRNBINN
;
OLDTEL:	0		;-1 USING OLD TELNET PROTOCOL
NEWTEL:	0		;-1 USING NEW TELNET PROTOCOL
SUPDUP:	0		;-1 USING (NEW) SUPDUP PROTOCOL
SUPNGF:	0		;-1 => EXPECTING SUPDUP VS TELNET NEGOTIATION
			; Only one of NCPP, CHAOSP, or TCPP can be set.
NCPP:	0		;-1 => WE'RE USING ARPA NCP
CHAOSP:	0		;-1 => WE'RE USING CHAOS NET
TCPP:	0		;-1 => WE'RE USING INTERNET TCP
ECOSTS:	NT%DO		;INITIAL ECHO STATE (REMOTE ECHO)
SGASTS:	-1		;LH -1 => WILL, RH -1 => DO   (TO AVOID INFINITE LOOPS)
DEBUG:	0		;NONZERO DEBUGGING, LEAVE SELF AROUND; ALSO DON'T TIME OUT THE ICP.
			;NEGATIVE => UNDER A DDT, SO DON'T TRY TO LOG IN.
TAFJPC:	0		;WHERE TERMINATED FROM

By the way, ASCIZ means a null-terminated ASCII string, like in C.
Well, I have to go hack now, hope I'm done before this sunny day goes away.
I'll get your expresso machine component and bring it down next week.  Ciao!