Bc2000 (for the BCF2000 & BCR2000)

The RM50 definition file is coming along, but wow, is it ever long.  That is a consequence of the RM50 being a drum synth, with separate settings for practically every note of every preset.

I managed to get around most of the complicated hi val/low val problems by using a fixed value for the hi vals, but I have some of questions about irregular low vals/low val ranges.  (Except where otherwise indicated, none of these have an accompanying hi val.)

1) There are some parameters which define the range as:

0-15 [bit3 = sign bit, 1 = (-), 0 = (+)]

What does the bit3 section mean?

2) There's a parameter which sets the low val range as:

low 7b -15 to +15 2' comp

Do I just represent this as a val with a range of 0-31?  What does the 2' comp part mean?

3) There's a parameter for the velocity curve that says:

Hi Val:
high 1bit

Low Val:
0-11

There are only 12 settings for the velocity curve.  Why did they put anything in the Hi Val column?

4) A few of the parameters have a split low val range of:

1-31, 33-122

Can I just set the range to 1-122?  What's the best way to handle this?