I don't remember it well, I think you need to visit visa/MC website. I had setup long ago when OTP option were not even available, so continued with that.
Since DCB is different network, not sure if this option available with them.
We can either use the physical pin you got for Addon card or call HDFC CC ask them for green pin, after that you would receive a OTP that's valid for a month and you can go to HDFC ATM and change it.
HDFC is the only Bank I know issues addon cards with same credit card number as the Primary. When I check the Card usage controls, it has online usage controls for addon cards as well. One issue/inconvenince I have is that whenever a online transaction is initiated, OTP comes to my mobile rather...
I had to call customer care to get confirmation, it was never mentioned in the statement. I had used my Regalia for years without knowing that it is LTF.