A digi-link card is a contact closure card. It is programmed exactly the same as a Chelsea switch. (See: Programming a Chelsea Switch) A digi-link card can have either 6 or 14 inputs since these are AP Digi-Link, a 6 will be set up as either a 8 or 14 button switch depending on the AO function desired. Each input on the card is represented as a button. If all inputs are to be disabled at one time then a D-6 can be set as a 8 button so buttons 7&8 can be accessed for AP functions. If individual inputs of the D-6 are to be disabled then the D-6 must be set as a 1 4 button switch.
When an input# becomes electrically connected to the local ground on the digi-link card, it triggers that input number.