Mailing machine having a user interface controller safety interlock to provide protection from hazardous voltages

A docking board for coupling a removable user interface controller to a machine, said docking board comprising:

• a docking connector to couple with said removable user interface;
• and
• a relay having a coil and a plurality of contacts, a first end of said coil being coupled to a first pin of said docking connector, a first portion of said plurality of contacts being coupled to respective other pins of said docking connector, a second portion of said plurality of contacts being coupled to a signal line,
• wherein said coil is powered thereby causing said plurality of contacts to close and couple said signal line to said respective pins of said docking connector only when said removable user interface is coupled with said docking connector.

A safety interlock for preventing a voltage signal from occurring on a first connector when said first connector is accessible to a user, said safety interlock comprising:

• a relay having a coil and a plurality of contacts, a first end of said coil being coupled to a first pin of said first connector, a first portion of said plurality of contacts being coupled to respective other pins of said first connector, a second portion of said plurality of contacts being coupled to a signal line, said signal line conducting said voltage signal;
• a second connector adapted to mate with said first connector, said second connector having a plurality of pins, said first connector being inaccessible to a user when said second connector is coupled to said first connector;
• and
• a bridging conductor to couple a first of said plurality of pins of said second connector to a second of said plurality of pins of said second connector, said bridging conductor conducting a supply voltage received from said first connector on said first pin of said second connector to said second pin of said second connector, said second pin of said second connector providing said supply voltage back to said first pin of said first connector, said first pin of said first connector providing said supply voltage to said coil of said relay to power said coil,
• wherein said coil is powered thereby causing said plurality of contacts to close and couple said signal line to said respective pins of said first connector only when said second connector is coupled with said first connector.