Hi Drwho.  Was reading parts of the Mitsubishi-900 service manual (albeit
a cruddy manual at best) and came across a sheet labeled 'Diagnostic Mode',
only it's stamped at the top with a "Mitsubishi Model 800 Transportable.."
like it's actually for the 800.  After playing around with my 900 handheld
this evening, I've come to the conclusion that the test-mode commands for
both phones must be nearly identical (i.e. all the commands work on the 900
as far as I can tell).  The only difference seems to be the code used to
punch into test-mode in the first place... the sheet says to use
[STO] + the 7 digit test code within 10 seconds after powering-up (i.e.
[STO] + 5278764)  For the 900, it's [END] + 0944635  (same as for the
Mitsubishi 3000).

Other than booting into test mode, all commands given for the 800 appear
to work just fine on the 900, though I'm not absolutely sure these are
all the test-mode commands available... I only have this one sheet and
am unable to tell whether the list might've been continued on the next
page or not.

A couple of the commands are rather puzzling; hard to tell exactly what
they do without more documentation.  I *did* get the "Wide-Band on" (23)
to work for me *once*: it produced this funky set of verticle lines that
appeared to writhe in time with the control channel data; when I'd change
to another (weaker) channel, they'd significantly change (usually to one
side or the other) sortta like a little spectrum analyzer or something.
Hard to tell more about this mode 'cause I've been unable to get the
phone switched into it again... must have something to do with one of the
other options I was playing with before trying (23)??

Anyway, here's the list of commands.

     -V


Mitsubishi 900 test mode
------------------------

first, power on.
Then, hold [END] key while entering 0944635.
Release [END] key.
You are now in test mode.

The program ROM version will be displayed.  The radio will
now accept commands as follows:

01 [SEND]     Tx on
02 [SEND]     Tx off
03 [SEND]     Rx unmute (scroll through channels with [*] and [#] keys)
04 [SEND]     Rx mute
05 [SEND]     Tx unmute
06 [SEND]     Tx mute
07 [SEND]     ST on
08 [SEND]     ST off
09 [SEND]     High Tone on
10 [SEND]     High Tone off
11 [SEND]     Low Tone on
12 [SEND]     Low Tone off
13 [SEND]     Handset Mode
14 [SEND]     Handsfree Mode
15 [SEND]     ??? (displays: 000)
16 [SEND]     Compandor on
17 [SEND]     Compandor off
18 [SEND]     Display ESN in hex
19 [SEND]     Non-Volatile Memory clear
20 [SEND]     Horn alert on
21 [SEND]     Horn alert off
22 [SEND]     Display NAM ([SEND] to cycle, [END] to quit)
23 [SEND]     Wide-Band on
24 [SEND]     Wide-Band off
25 [SEND]     Status Monitor on
26 [SEND]     Status Monitor off
27 [SEND]     SYNTH/AP/HS power save on
28 [SEND]     SYNTH/AP/HS power save off
29 [SEND]     ???
30 [SEND]     DTMF off
4n [SEND]     DTMF on (n=0-9)
50 [SEND]     AP Pass Direct
51 [SEND]     AP Pass Normal
80 [SEND]     SAT off
81 [SEND]     SAT 5970 Hz on
82 [SEND]     SAT 6000 Hz on
83 [SEND]     SAT 6030 Hz on
9n [SEND]     Set RF output power level (n=0-7)


69 [SEND]     LCD Display test ([CLEAR] to restore screen)

While in test mode, the current cellular channel number can be incremented
with the [#] key and decremented by the [*] key.  Successive presses of
the [RCL] key sets the phone to one of three channels: 0384, 0799, or 0991.
Successive presses of the [STO] key seems to set the attenuation of the
receiver's audio output to one of three set levels: AP ATT8, AP ATTB, or
AP ATTE; likewise, pressing [VOL] allows stepping through each different
attenuation level from AP ATT8 (softest), AP ATT9, etc. through
AP ATTE (loudest).  Hitting [FCN] samples the current received signal
strength and displays it as a three digit numeric.


-end