Article reference KA-02167
The VX100 uses the same fan body and terminal block as some other model including some timer variants, which is why the back plate has the T terminal labelled. However, as there is no PCB contained in it, it does not have the provision for a timer feature.
VX100 terminal
VX100T terminal
If you would like to know how to wire the timer on the VX100T, click the below link:
Where do I connect the switched live wire on the Xpelair VX100T-SP fan?