Receive only expansion:
------------------------
1) Turn radio off
2) Press [B]+[#] switch and turn ON radio.
   Depress [B] and [#] only when the display shows all functions and
   the radio emits a beep.
3) Go to SET mode and a new function will appear after TONE selection.The
   new function is designed by PL. Set PL to "1"for 1 MHz frqcy. enter,
   to 10 for 10 MHz frqcy. enter and to 100 for 100 MHz frqcy. enter
   resolution.

Note1: This modification does not reset information saved on the CPU.
Note2: Frequency range is 50,0-107,995 MHz FM
                         108,0-135,995 MHz AM (aviation band)
                         136,0-299,900 MHz FM
                             for the VHF portion;
                         300,0-999,900 MHz FM for the UHF portion.

TRANSMIT EXPANSION:
-------------------
1) Call Icom Parts Dept. and order one diode MA132WK (D.23) for IC-W21AT,
   Symbol: MU;
2) Open radio and localize the logic unit;
   The logic unit is the half portion of the radio that contains the CPU,
   display, keyboard, etc...;
3) Localize some orange colour components in the lowset right part of the
   portion, below the CPU shield plate.
   Localize the smallest orange colour component. Note a empty place for a
   surface mount diode (3 dots) near this orange component (see draw below);

   ------\   :  .  <---- Empty place for surface mount diode MA132WK
   |oran- \                                   -----------| | DIAL button
   | ge   /  :<>.  <---- Surface mount diode  |    CPU   | |
   ----- /                   mounted          |  Shield  | | U vol button
     ^                                        |   Plate  . |
     |                                        .          . | V vol button
     |Smallest orange colour component  ------|------------|
                                               ---PTT,F,Moni..

4) Add D23 MA132WK diode in the empty place.
   Do use very fine soldering iron and temperature controlated gear.
   The circuit is very fragile and may burn if excecive heat is applied.
   Take care for static damage also; If you can, use professional gear
   for this purpose or find technical assistance of your choice.

      
-FULL CROSS BAND REPEATER OPERATION-
This feature enables HT to receive on one band and retransmit the content to
the other band. You can even choose tone squelsh selections, repeater offsets
and many other features available during normal operation.
1)Select frequencies on VHF&UHF and options (tones, DUP,...);
2)Set "key lock" by pushing [F]+[C] keys. Then turn radio off;
3)Push [F]+[MONI]+[RPT-M] keys and while holding them pressed, turn radio
on. You will get flashing "L", telling you cross band rpt. is enable.
4)Press [F]+[C] ("key lock" release) and you will clear the cross band rpt.
mode.

==============================================================================

The Icom IC W21AT handi-talkie normally receives two bands:
136 to 174 MHz and 440 to 450 MHz.

You can program it to receive
50 to 300 MHz and 300 to 999 MHz.

To do this, turn it off, then simultaneously hold down
the # and the B keys while turning it on.  Keep them pressed
for 2 seconds after turning the rig on. 

The LCD display will go through a self test, and you'll
then have a wideband receiver.  It's not very sensitive
far from the ham bands, but it's handy for listening to
6 Meters or as a portable scanner.

Note that this modification does not require any cutting of
diodes or rewiring -- it's entirely front panel.