Howdy,
since I am curious by profession (electronics engineer), I connected my trusty Tektronix scope to the remote interface of my PCM-M10. This is what I found:
Connector:
4-pole 3.5mm plug
tip = cathode "Recording" LED in remote
ring 1 = data
ring 2 = ground
sleeve = +3V, anode "Recording" LED
data protocol:
Sony SIRC, unmodulated (i.e. lacking the 40kHz carrier),
Start bit + 20 data bits: 7 command bits, 5 device address bits, 8 extra bits (all LSB first)
The following commands are sent in the sequence "start bit - command bits - device address - extra bits":
TMARK: $48-$1A-$E4 (S-0001001-01011-00100111)
STOP: $18-$1A-$E4 (S-0001100-01011-00100111)
PAUSE: $19-$1A-$E4 (S-1001100-01011-00100111)
REC: $1D-$1A-$E4 (S-1011100-01011-00100111)
Interestingly, the device address is in the group for Blu-ray recorders, as listed on this page:
http://www.hifi-remote.com/sony/The missing commands between "PAUSE" and "REC" are (at least in the Blu-ray recorders): $1A, "PLAY", $1B, "<<" and $1C, ">>".
Maybe they are implemented in the M10?
Since I cannot guarantee that my findings are 100% correct, proceed with caution and use the information presented here at your own risk.
Greetings,
Rainer