Here is the extended function code map for the Sony PCM-R500 DAT recorder.
I expect that they may also work for other Sony DAT recorders like the
PCM-2600, but someone else will have to verify that.

Device code = VCR/0093

Number Keys
===========
    ** Not particularly useful (unless you want to scramble your number
    ** keys, or you really really want a "10" key for some reason).

075 0
010 1
014 2
008 3
012 4
011 5
015 6
009 7
013 8
138 9
142 10

Display Control
===============

201 Clear
232 Counter Reset
238 Counter Mode
    ** These 3 exist on both the RM-D757 and RM-D750 remote
110 Current Date (Cycle: Date/Time/Return to Previous display mode)
104 Date Of Recording (Cycle: Date/Time/Return to Previous display mode)
153 Margin Reset
    ** These 3 exist only on the RM-D750 remote
233 Absolute Time (Direct)
106 Remaining Time (Direct)
239 Program Time (Direct)
237 Tape Running Time (Direct)
    ** These 4 don't appear on either remote. They go directly to
    ** a particular display mode. Obviously you can get there by pressing
    ** the counter mode button multiple times.
156 Display Control (Cycle: On/Meters Off/All Off)
    ** I don't think this functionality exists on the RM-D750. I have no
    ** reason to turn off my display, but I know other devices have this
    ** functionality, so somebody must care.


Subcodes
========
092 Renumber
090 Auto Start Id
250 Start Id Rehearsal
094 Start Id Write
088 Start Id Erase
254 Skip Id Rehearsal
091 Skip Id Write
095 Skip Id Erase
218 End Id Write
248 End Id Rehearsal
222 End Id Erase
    ** These all exist on the RM-D750 remote

Basic Operations
================
234 Open/Close
170 Stop
168 Play
171 Fast Forward
174 Pause
172 Rewind
175 Record
173 Record Mute
    ** These all exist on both remotes
169 One Button Record (no pause)
    ** Doesn't exist on either remote. Kind of dangerous. Note that
    ** the record key on the One-For-All remotes have to be pressed
    ** twice, no matter what function is mapped to it. So in this case
    ** it might not be as dangerous.
093 Rewind and Play
    ** Doesn't exist on either remote. This is the same function as
    ** when you press the rewind key on the recorder, hold it down, and
    ** then press the play key. You can't do this with the Sony remotes.


Advanced Play
=============
041 Repeat
122 Previous (AMS)
126 Next (AMS)
    ** These 3 exist on both remotes
108 Mark
107 Locate
123 Music Scan
204 RMS Enter
207 RMS Check
220 Skip Play
    ** These 6 exist only on the RM-D750 remote
Misc
----
221 Fader (PCM-R700 only)
040 Input Monitor / Source
    ** These 2 exist only on the RM-D750. Note that even though the
    ** PCM-R500 does not have 4 heads (like the PCM-R700), the Input
    ** Monitor button can still be useful. If you don't have a tape
    ** in the machine you can monitor the input by pressing record
    ** and the deck will display "SOURCE" (after displaying "NO TAPE")
    ** and let you monitor the input. However, if you have a tape in
    ** the machine, pressing record will put the machine in record pause
    ** mode, causing wear on the heads and tape. Using this button will
    ** allow you to monitor the input in cases where you may not want
    ** to start recording immediately.
235 Clock Set
    ** Doesn't exist on either remote. Doesn't seem very useful, since
    ** you still need to use the data wheel to change values. It saves
    ** you from having to cycle through all of the menu items to find
    ** the clock set menu. But I am not in the habit of setting my
    ** date and time all that often anyway!
060 Show ID6 (Temporarily and then return to previous)
    ** Doesn't exist on either remote
061 Show ???
    ** Shows some Hex numbers, similar to many of the obscure displays
    ** you can get with the below function, but I have no idea what it
    ** is. It only displays temporarily and then returns to the former
    ** display item.
089 Diagnostics
    ** This is the one you need to get the error codes. You can enter
    ** 91 followed by this key. I tried a few other number combinations.
    ** Most don't do anything or display some obscure hex digits. Here
    ** are the ones that did something different:

    80  -- Resets current date and time.
    89  -- All lights on. Every possibly display element lights up
    91  -- Displays playback error counts for the A & B heads. Displays
           an "A" followed by 8 hex digits. The first 4 are the error
           counts for the A head, the second 4 are for the B head.
    97  -- Displays GENERL CAT or DAT CAT at various times. I haven't
           figured out its meaning.
    99  -- Set current date and time (same as extended function 235 
above)

    Can anyone else can fill in the meaning of the other mysterious
    hex displays?

    I hope that others find this information useful.

    John Marvin
    jsm@fc.hp.com