VL2221 duplex disabled when connected to Jamex coin box

[Techead42]

One of our technicians is attempting to connect a Jamex 6557 coin box to a Konica Minolta VL2221; the unit can be connected but then duplex is disabled on the copier. The tech has set the VL2221 to Vendor 1 which allows the unit to operate, but in order to allow duplex copying it needs to be set to Vendor 2...yet when set to Vendor 2, he gets the message "Turn Vending Unit On" displayed on the control panel.

Does anyone here have any information on this?

Thanks.