Cannon 19 pin data connector. SK19-21C-1/2. SK19-32SL.

PGK.pdf from 

http://www.peigenesis.com/images/products/pdf/FullSpec%20PGK.pdf

order for over $125 from http://www.peigenesis.com/

references courtesy of Tom Mikulic http://tomislavmikulic.com/proj-565.html


In PGK catalog;

following steps,
1) number of contacts suggesst SK-19, #16 wires
2) shell style is 32SL for receptacle on plotter
   shell style would be 21C for mating cable straight plug
3) cable clamp would be 1/2, 5/8, or 3/4 for cable
4) rotation would be N (no rotation) both connectors
5) shell plating omitted
6) part numbers become:
-- on plotter SK19-32SL
-- on cable   SK19-21C-1/2 (or 5/8 or 3/4)

SK19 couping diameter is 1-5/16'
coresponding plug is K-21C, coupling nut diameter is 1-15/32

looks like plotter has K-32SL large flange connector
if so spacing between screws is 1.280 
height of threaded section is 7/16"
thread is 1-5/16-6

pins are numbered right to left (3 2 1) top to bottom

   3 2 1
  7 6 5 4 
 12 11 10 9 8
 16 15 14 13
  19 18 17



my rough measurements

Screws are 1.3" apart
diameter of threaded section is 1.25 inches very roughly
inside diameter is 1-1/8
pin are about .060 to .062 (under .0625 or 1/16 tubing)
pin spacing .2 inch

Mikulic rough measurements (may 10 2010) are

pin 1.60 mm (.063 inch)
inner diameter 28.67 (1.129 inch)
outer diameter 32.41 (1.276 inch)
mounting holes 33.20mm (1.307 inch)
pin lengths 10.14 (.4 inch)
shell depth 11.31 (.445 inch))