A Tale of Two CTYs

This file explains how to set up a WAITS CTY on the normal TTY scanner,
either in place of, or in addition to, the normal CTY.  This feature
currently is not available on the CCRMA F2 version of WAITS, although it
could be made to work there with only a small amount of effort.

Assume that you want to make DCA port 55 be the CTY, and assume the
TTY number of the CTY is 160.  If not, alter these instructions
correspondingly.


(0) Make sure that the system doesn't think TTY55 is a display.  If it
does, do a TTY TTY55 NO DM command (or just TTY NO DM on TTY55).  Make
sure that worked.

(1) Hopefully the DCA port will already have been set up by the system
to run at the right speed; if not, TTY TTY55 SPEED nnnn, where nnnn is
the correct baud rate, will set the speed.  This may not work if you
have already done step (2) below.  If you have done that step and the
above command doesn't work, then try TTY TTY160 SPEED nnnn.

(2) Set the low 7 bits of DCATAB+55 to 160 instead of 55.

(3) Set the right half of LINBIT+160 to 400055 instead of 0

(4) Set the cell SCNCTY to 55 instead of -1.

(5) If you want duplicate output on both the real CTY and the scanner
CTY, then zero the cell SUPCTY (else leave it -1).

(6) If you want parallel input from both the real CTY and the scanner
CTY, then zero the cell SUICTY (else leave it -1).


Now normal TTY and EDDT type-in and type-out should work from the
scanner CTY of your choice.  To undo this, restore the normal values
(from the "instead of" phrases above) changed in steps (2) through (4)
above.  The values of SUICTY and SUPCTY are irrelevant if SCNCTY is -1.


(7) The command CTY 55<cr> given on (any) CTY will execute step (4).
The command CTY$ given on (any) CTY, where $ is altmode, will undo
step (4).  (It is possible that this might screw up leaving TOIP set
in the CTY's TTY DDB, which means you won't get any output!)  These
commands can alternatively be given from a privileged (DEV priv) job.