Unicomp PC 122 keymatrix simulator

This interactive tool simulates the keyboard matrix (keymatrix) of a Unicomp PC 122 so that you can test if possible key combinations work without needing to test on a physical keyboard. Model Ms are all fundamentally two-key rollover (2KRO) keyboards due to the use of a membrane assembly, but this doesn't mean Model Ms cannot register more than 2 keys unlike popular belief. This tool demonstrates this and can allow you to see if a given Model M keymatrix would be suitable for your needs.

Disclaimer & notes

This tool is intended to be a guideline only. The results from any input are based on physical keymatrix data only and doesn't take into account firmware (ie, differing deghosting algorithm implementations or bugs/quirks). If you're using this tool as part of a purchasing decision, if possible, it would be prudent to try verifying results on a real keyboard someone you know has or ask on /r/modelm subreddit. The tool is also best viewed on desktop.

Keyboard simulator (5250)

F13
F14
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F20
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F22
F23
F24
F1
F2
F3
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F12
SysRq Attn
ScrLk
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1
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0
-
=
Backspace
Back Tab
Dup
RollDn
End
NumLk
Num /
Num *
Print Screen
Clear
Tab
Q
W
E
R
T
Y
U
I
O
P
[
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Field Exit
Return
Delete
RollUp
Num 7
Num 8
Num 9
Field -
Print
Help
Caps Lock
A
S
D
F
G
H
J
K
L
;
'
\
Up
Num 4
Num 5
Num 6
Field +
Record
Play
LShift
N/A 1
Z
X
C
V
B
N
M
,
.
/
RShift
Left
Home
Right
Num 1
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Num 3
Num Field Exit
GUI
Menu
Reset
LAlt
Space
RAlt
Enter
Down
Num 0
Num .
Switch to 3270

Only US English functional layout is available for the 5250 simulator at this time

Key

Firmware caution: A 3-key combination that may or may not be problematic depending on keyboard's firmware. A custom QMK-based controller would probably be fine with these, but IBM/Lexmark/Unicomp native firmware may not.
Hardware block: A N-key combination that will block in any circumstance due to the matrix's design. There is nothing you can do about these since they're a fundamental keymatrix limitation.

Matrix

This is a tabular representation of the data used by the simulator above. A keyboard matrix is constructed from a series of columns (X-axis) and rows (Y-axis) whose intersections are used for key assignment. Such matrices allows a large number of keys to be driven by relatively few traces, as opposed to each key requiring its own circuit.

0 1 2 3 4 5 6 7 8 9 A B C D E F
0 k_lb1 k_lb4 k_f3 k_f1 k_ins k_3 k_4 k_6 k_f5 k_f7 k_f9 k_f11 k_lb3 k_right k_lb2 k_lb6
1 k_tab k_f21 k_del k_pgdn k_f22 k_e k_t k_u k_backspace k_minus k_down k_end k_home k_f23 k_f14 k_caps
2 k_1 k_f19 kp_nl k_pgup k_f17 k_i k_r k_y k_equals k_9 k_0 kp_mult kp_div k_up k_lb9 k_f16
3 k_q k_rshift kp_9 k_2 KC_NO k_k k_f k_h k_rbrc k_o k_semicolon kp_8 kp_7 k_f24 k_f13 k_lctrl
4 k_a KC_NO kp_6 k_w k_lalt k_d k_g k_j k_backsl k_lbrc k_singlequote kp_5 kp_4 k_f20 k_f15 k_lb10
5 k_z k_lshift kp_dot k_x KC_NO k_cm k_b k_m k_return k_period k_p kp_0 kp_1 k_navmid kp_plus_hidden k_rctrl
6 k_nubs KC_NO kp_3 k_s k_ralt k_c k_v k_n k_left k_l k_fwslash kp_2 kp_plus k_nuhs k_lb7 KC_NO
7 k_tild k_f18 kp_minus k_f2 k_f4 k_8 k_5 k_7 k_f6 k_f8 k_f10 k_f12 k_lb8 k_space kp_enter k_lb5

More info