Date   : Wed, 23 Nov 1983 10:47:07-EST
From   : Frank da Cruz <cc.fdc@COLUMBIA-20.ARPA>
Subject: KERMIT and TAC

I've been told by someone who knows about these things (Mark Crispin at
Stanford) that there's no good way to make KERMIT-20 put the TAC in binary
mode, at least not in a way that doesn't depend on a bug in TOPS-20 that may be
present at some sites but fixed at others (the bug being that FF (a byte with
all 1's) is supposed to be quoted by doubling in the monitor, but isn't, so
some application programs do it instead).  Therefore, the way to use KERMIT
over a TAC would seem to be:

1. Set the TAC escape character to be any control character other than ^A or
CR, LF, etc.  ^A is KERMIT's packet synchronization character, and CR or LF
might be used as line terminators at the end of packets (KERMIT never puts any
control characters inside the packets).  Also, choose the character to be
something you're unlikely to type during your timesharing session.  For
instance, as Keith Petersen suggests, use ^E.  Do this by typing "@I 5" (for
^E) to the TAC.  This allows "@" to be transmitted.

2. To send binary files, type "@B O S" and "@B I S" to the TAC (if you already
did step 1, then I suppose you would type "^EB O S" and "^EB I S").

I'm not a TAC user myself, so I can't vouch for any of this.  - Frank