Here is what I discovered for the Elektex keyboard.

http://www.elektex.com/

Also known as the Mobis Just Mobile RoKy^2 and the 5250 G-Tech Wireless Fabric
Keyboard

www.mobis.com.tw
www.just-mobileonline.com
www.g-techworld.com

All numbers below are in decimal.

When not pressing any key you get a stream of 255.
When pressing and releasing any key, no matter whether it is a shift key, you
get one specific number when pressing the key and another specific number when
releasing the key. The release code appears to be 128+the press code. The
press codes appear to be ASCII, except for the non-ASCII keys: Caps, Shift,
Uparrow, Ctrl, Alt, AltGr, Leftarrow, Downarrow, and Rightarrow. The Left and
Right Shift keys send the same press/release codes. These are the only two
keys that do so. Also, it appears that it is not possible to distinguish
between the release of Del and the background stream of 255 since they are
both coded as 255. Below is a complete table giving the press and release
codes for each key, along with both the unshifted and shifted symbols on the
key. Note that the 4 key has two shifted symbols and is the only key that has
such.

If you press and hold a key then you get a stream of press codes but then a
single release code when releasing the key. If you press one key, hold it, and
press a second key and hold it while still holding the first key, you get a
press code for the first key until you press the second key, then you get
nothing (except stream of 255s) from the time you press the second key until
you release both keys. Then you get a single press code for the second key and
then a single instance of the release codes for both keys. If you press and
hold three keys you only get (a stream of) press code(s) for the first key
until you press the second key, then nothing (except stream of 255s) until you
release all three keys then you get a press code for just the second key but
not the third and you get release codes for just the first two keys but not
the third. Sometimes you don't get the release codes but get a 248 instead.
Sometimes, even when you press and release two keys quickly together you get a
248. It seems to be some form of roll-over indicator.

There is no difference between modifier and non-modifier keys.

Press Shift Press A Release Shift Release A gives:
   got: 2
   key press: 42
   got: 65
   chorded key press: 30
   got: 193
   chorded key release: 30
   got: 130
   key release: 42

Press Shift Press A Release A Release Shift gives:
   got: 2
   key press: 42
   got: 248
   unrecognized release code
   got: 130
   key release: 42

Press and Hold Shift Press A Release A Release Shift gives:
   got: 2
   key press: 42
   got: 2
   repeat key press: 42
   got: 2
   repeat key press: 42
   got: 2
   repeat key press: 42
   got: 248
   unrecognized release code
   got: 130
   key release: 42

Because of the above, it appears possible to recognize chording of the form:

  Press A Press B Release A Release B

but impossible to recognize chording of the form:

  Press A Press B Release B Release A

This makes modifier chording tricky. It also appears impossible to recognize
chording of more than two keys. This precludes double modifier chording like
Ctrl-Alt-... or Alt-Shift-....

The Elektex drivers implement modifier keys as prefix keys. My driver does this
as well. My driver supports two ways to type singly modified keystrokes:

  Press Modifier Press Key Release Modifier Release Key

and:

  Press Modifier Release Modifier Press Key Release Key

The keys (Left and Right) Shift, Ctrl, Alt, and AltGr are treated as modifiers.
Each press and release of a modifier toggles whether the next key is so
modified. Thus:

  Press Modifier Release Modifier Press Modifier Release Modifier

does not modify the next keystroke. You can doubly modify a keystroke with

  Press Modifier1 Release Modifier1 Press Modifier2 Release Modifier2
  Press Key Release Key

Similarly for triple modification and higher. Such modification applies to the
autorepeat of a keystroke.

Key        Shifted  Press Release
---------------------------------
ESC                 27    155
1          !        49    177
2          "        50    178
3          Sterling 51    179
4          $ Euro   52    180
5          %        53    181
6          ^        54    182
7          &        55    183
8          *        56    184
9          (        57    185
0          )        48    176
-          _        45    173
=          +        61    189
Backspace            8    136
Tab                  9    137
Q                   81    209
W                   87    215
E                   69    197
R                   82    210
T                   84    212
Y                   89    217
U                   85    213
I                   73    201
O                   79    207
P                   80    208
[          {        91    219
]          }        93    221
Caps                 3    131
A                   65    193
S                   83    211
D                   68    196
F                   70    198
G                   71    199
H                   72    200
J                   74    202
K                   75    203
L                   76    204
;          :        59    187
'          @        39    167
#          ~        35    163
Enter               13    141
Shift                2    130
\          |        92    220
Z                   90    218
X                   88    216
C                   67    195
V                   86    214
B                   66    194
N                   78    206
M                   77    205
,          <        44    172
.          >        46    174
/          ?        47    175
Uparrow             20    148
Shift                2    130
Ctrl               112    240
Alt                113    241
Space               32    160
AltGr              114    242
Del                127    255
Leftarrow           22    150
Downarrow           21    149
Rightarrow          23    151

They keyboard layout differs somewhat from the standard:
  Shift 2 is " while on most keyboards it is @.
  Shift 3 is sterling while on most keyboards it is #.
  Shift ' is @ while on most keyboards it is ".
  There is a key in a nonstandard location where # is unshifted and ~ is
  shifted.
  There is no ` key. This is the only missing key.
  The key with unshifted \ and shifted | is in a nonstandard location.
  There is a euro symbol on the 4 key along with $.

Because of the above, the driver operates in two modes:
  elektex: the key labels are observed except that sterling generates ` and it
           is not possible to generate sterling or euro
  elektex_unmapped: shift 2 (i.e. ") generates @
                    shift 3 (i.e. sterling) generates #
                    shift ' (i.e. @) generates "
                    # generates `
                    not possible to generate sterling or euro

There are 19 of these upon startup:
   got: 165
   transitioning to state 1
   got: 0
   transitioning to state 2
   got: 1
   transitioning to state 3
   got: 90
   165, 0, 1, 90 ignored
I don't know what these are for. They are ignored.

The drivers provided by Elektex support additional functionality:
  Setting sensitivity
  Setting key repeat rate
  Setting key repeat delay
  Audible keyclicks
  Setting connection timeout
  Calibration
  Reading battery status
I don't know how to access this functionality.

http://www.g-techworld.com/Drivers/5250/ETP-1833_GTECH_Fabric%20Keyboard%20USER%20GUIDE%20v1.0.pdf

Sometimes I get the message:

   evdev open: No such file or directory
