There are 5 different add-on software licenses available. You will need one of the add-on licenses if you use a higher layer protocol such as CANopen, J1939, DeviceNet. There are also options for using a Protocol Monitor for one of these protocols. If you just use plain CAN, you may consider the Protocol Monitor CAN-License key for Protocol Monitor CAN (transmit / receive). The available licenses are as follows: CAN-Bus Tester 2: CANopen bus add-on $1039 CAN-Bus Tester 2: DeviceNet bus add-on $1239 CAN-Bus Tester 2: J1939 bus add-on $659 CAN-Bus Tester 2: Protocol Monitor CAN (Rx/Tx) $649 CAN-Bus Tester 2: Protocol Monitor CANopen (Receive) $519 CAN-Bus Tester 2: Protocol Monitor J1939 (Receive) $519