A late response:Gnaeus wrote: The second one is a more common teller's mark, with Arabic (?) script at left.
Last year I was on holiday in Thailand and I saw somewhere a symbol on the street.
I had seen that symbol before! After returning home I saw Androl had posted the same stamp.
After looked over my collection I have noticed that it was just like the charakter on Gnaeus banknote.
It kept me busy what it was. When viewing the old ATM vouchers, I thought of that charakter again.
And I found it!
The sign on the banknote is the logo of the Thanachart Bank Public Company Limited (TBANK), aka Thanachart Bank in Bangkok, Thailand.

One mystery solved.













