The F3 key or Busy On a Call status is a button that changes the unit's status to Busy On a Call.
When a unit is in the Busy On a Call status, other units and dispatch are able to determine
that this unit cannot take calls or assist other units. This feature is focused more on
patrol units that are able to freely move between accounts and assist other units.
When a unit changes status, other units and the dispatcher are able to view
this unit's status and determine whether they are available or busy. There
are six total statuses a unit can be in.
Below you will see an example of what your dispatcher would see.
The dispatcher will be able to see how many units are online and
what status they are currently in. Below you will see that the unit
is currently in the Busy On a Call status which is denoted by a yellow status color.