Thanks to Chris Iffland's useful information on hacking into the MZ-R2 remote I have built a more robust remote box for my MZ-R30. Resistor values between pins 2 & 4 are very similar to the MZ-R2, with a couple of additions:
<< 1k >>/play 3.62k pause 5.15k Stop 7k Vol down 8.4k Vol up 9.9k Mark 11.9kThe following aren't on the MZ-R30 remote but are very useful:
Mode 14k Display 17k Record 19.5k Test mode 24k (use at your own risk!)