Glendinning electronic engine control components are connected to each other, in series, via cables connected to CANbus ports.
Each component (Control Head, Control Processor, etc.) has 2 ports, so they can be linked to each other.
This means that the last component at either end of the "chain" of components in the system will have an unused port.
These terminal ports will require a terminating resistor to be plugged into the empty port.
Generally, this means one in the remaining empty port in the last/furthest Control Station, and one in the remaining empty port in the Control Processor box - fro a total of two terminating resistors.
However, in installations where each Control Head is linked independently to the EEC Control Processor, each will require a terminating resistor.