Re: Xbus terminators

[MOON@MIT-AI]

CC: H at MIT-AI
The assignments of the 12 SIPs on the Xbus terminator are as follows:
	first 6 - data lines except bit 0
	next 4 - address lines and data bit 0
	bottom 2 - control lines

The existing terminators are as follows:
	CADR1,CADR3,CADR5 - all 180/390
	CADR2,CADR4 - 5 180/390, 5 162/260, 1 81/130, 1 162/260
	CADR6 - 5 180/390, 4 162/260, 1 180/390, 2 81/130
	CADR7 - 10 180/390, 1 81/130, 1 180/390

After thinking about it and scoping some signals, I think these
are all brain-damaged.  I propose that the right thing is:
	6 180/390
	4 162/260
	2 81/130
Anyone who disagrees please complain, otherwise we will adopt this.
Penny please add this to the parts lists.  Tom please make sure enough
of each kind get ordered.

I'm not sure if it makes any difference for the address lines to be
162/260 instead of 180/390 but I guess it can't hurt and it's probably
a good idea.