Ralph Hartley is the expert when it comes to different terminals,
how they work when jumpered differently, and their control units.
 
  The keys on a 3278 or 3279 keyboard will work depending on how the
keyboard is jumpered and the control unit the terminal is connected to.
To get to the four jumpers, take off the keyboard cover (there are four
flat-head screws underneath).  Set the keyboard right side up and the
four jumpers are on the left, underneath the plastic, above the clear
key.  They are all next to each other vertically, that is top to bottom,
and they are numbered 0-3, 0 being the top, 3 the bottom.
 
  You can see how the keyboard is jumpered without taking the cover off
by gettting into Test mode on the terminal and looking at the control
unit's control storage.  The way to do this differs depending on what
kind of control unit you're on.  If you have an "S" at the very far
bottom left corner of your screen (the Operator Information Area),
your terminal is connected to a 3174.  If you have a little "4" with a
box around it, you're connected to a 3274.
 
  For a 3174, Hit Alt-Test   to get into Test mode,
                  PF12       Test Menu
                  6 <Enter>  Display Control Areas
                  2 <Enter>  Port control area (requestor's port)
  Look at byte 09.
 
  For a 3274, know your port # in decimal (hex 00-1F = Decimal 00-31)
  Hit Alt-Test       to get into Test mode,
      ##/6 <Enter>   where ## is your decimal port #.  Shows bytes 00-3F.
           <Enter>   Shows bytes 40-7F.
           <Enter>   Shows bytes 80-BF.  Look at byte 95.
 
For both kinds of control units, those two bytes are the same.  The
high order nibble tells you how the keyboard is jumpered, the next three
bits tell you the model of the terminal, and the last bit tells you
if there's a printer attached.
 
The following table shows the features of your keyboard for the most
common pluggings.  The first column is the value you see in the first
nibble of the control byte described above.  The second shows the
jumper plugging.  An "x" means there is a jumper there.  Notice that
the control byte is the hex equivalent of the jumper, where a jumper
is the 0 value (opposite of what you might guess).  The "Doc" column
shows whether the "Entry Assist" feature is enabled.  The "Clear"
column shows whether the Clear and PA keys require 1 finger or 2.
If 2, you need to hold down the ALT key at the same time as the other
key.  The next 3 columns show what you get using the PF keypad by
itself, with the shift key, and with the ALT key.  A "NUM" means the
numeric keypad.  An "ERROR" or "ERR-2" are different error indicators
in the bottom row, the Operator's Information Area.  A "-" means that
nothing happens.  The next two columns show what you get with the
"<--" key on the top row, three keys up from the ENTER key, just to
the left of the PA1 key.  A "<--" means backspace.  "TEXT" or "APL"
turn on that mode, with those words appearing in the Operator's
Information Area.  Again, "-" means nothing happens.
 
At Almaden, keyboard types 1, 5, and 7 are most common.  I prefer 3.
 
 
    Plugging Control    Clear ----  PF Keys -----    "<--" Key
CB  0 1 2 3   Unit  DOC Keys  Plain  Shift  Alt-    Plain  Alt-
--  --------  ----  ---  --   -----  -----  -----   -----  -----
 1  x x x     3274  Yes   2    1-12   1-12    -      <--    APL
              3174  Yes   1    1-12    NUM  13-24    <--    APL
 2  x x   x   3274  No    1    1-12   1-12    -     TEXT     -
              3174  No    1    1-12   1-12    -     TEXT     -
 3  x x       3274* Yes   1    1-12    NUM  13-24    <--     -
              3174  Yes   1    1-12    NUM  13-24    <--     -
 4  x   x x   3274  Yes   2   13-24  Error  Error    <--     -
              3174  Yes   2   13-24  Err-2  Err-2    <--     -
 5  x   x     3274  Yes   2    1-12   1-12    -      <--    APL
              3174  Yes   1    1-12    NUM  13-24    <--    APL
 6  x     x   3274  No    1    1-12   1-12    -     TEXT     -
              3174  No    1    1-12   1-12    -     TEXT     -
 7  x         3274  Yes   2    1-12  Error  Error    <--    APL
              3174  Yes   1    1-12    NUM  13-24    <--    APL
 E        x   3274  Yes   2   13-24  13-24    -      <--     -
              3174  Yes   2   13-24  14-24    -      <--     -
 
 
* - With the wrong customization (question 125?) in the 3274 control
    unit, this keyboard will show an Err-1 type error on power up and
    act differently.  You will have 2-finger clear and PA keys, not
    single finger, the shifted PF keys will be PF 13-24, not the
    numeric keypad, and the Alt-PF keys will do nothing, not give you
    PF 13-24.
 
 
      To see how your terminal is configured,
  For a 3174, Hit Alt-Test   to get into Test mode,
                  PF12       Test Menu
                  2 <Enter>  Display configuration panels
                  2 <Enter>  Configuration questions
  The SNA port showed
  1st Panel:
     099 - CONFIG ON 050490  SNA PORTS 0 AT  1 SESS   PORTS 1 TO 31  4 SESSIONS
     100 - 01L
     101 - 5
 
                  PF8        Fwd
  2nd Panel:
     104 - 20           105 - 00          108 - 00H5948      110 - 5     116 - 1
     121 - 01           123 - 0           125 - 11001000     127 - 0 0
     132 - 0 0 1 1      136 - 1 1 0 1     137 - 0 0 0 0      138 - 2
     141 - A            165 - 0           166 - B            168 - 0
     173 - 00000000     175 -             178 - 0
     213 - 1            215 - 00000       220 - 0
     222 - 1            223 - 10          224 - 2            225 - 4
 
                  PF8        Fwd
  3rd Panel:
     500 - 0            501 - VMDSNA1_    502 - ENGESOFT