of beep also no use

This was my first time fined for driving through an ERP gantry without a cashcard.

On that very day, I forgot that the ERP was in operation and quickly inserted the cashcard into the In-Vehicle Unit. Then I waited about 5 seconds before passing through the gantry.

What I learnt is that even if the cashcard is placed into the IU and it beeped, the IU needs about 10 seconds for the cashcard to be fully activated.

So next time, I'll wait for more than 10 seconds.