They can be used together.
* 14/24-point type FX3G series main unit
・ An expansion board can be connected to BD1 (1st position) and a memory cassette can be connected to BD2 (2nd position).
* 40/60-point type FX3G series main unit
・ When one expansion board is used, a memory cassette can be connected to any BD slot where the expansion board is not connected.
・ When two expansion boards are used, a memory cassette can be connected to BD1 (2nd position) or BD2 (2nd position).