Here is the doc builder
http://www.ghielmetti.ch/download/gkv_nxm_321_621_la_e.pdf

using nothing compliqubr />
it is convenient to view patches & mmoriser (just take a picture of the matrices)
instead of all the cables of a modular
does not replace a cable that also serves as a ca signals mix and there are needles with LEDs to send message

I have a plan for EMS http://www.hinton-instruments.co.uk/ems/emsmods.html # matrix ( http://www.hinton-instruments.co.uk/ems/emsmods.html#matrix )

and one from Marc BAREILLES http://m.bareille.free.fr/asm1/matrix.gif

there is the EMS Synthi the Vostok analogous Systm using this system.
These are brand Sealectro matrices that is used for EMS Synthi