Don't know if it's relevant, but I/O card is powered by external 5v only, no 12v rails.
It goes straight into the input card of ttx, the one with usb labeled jamma, rj port, 2 leds and 5 dipswitches.
1, 2 and 5 are on.
Just tried again: jvs type 1 goes hassles free into multi, jvs type 2 no I/O...