Can anyone help with switching a PAYG SIM to another phone - both same network?

[letmehelp]

My ancient Vodafone PAYG mobile has finally died today.

I also have a Blackberry Curve, which is an old work phone I no longer use (they said I could keep it!) As it's also on Vodafone ATM, I was hoping it was just a matter of switching the SIM, but unfortunately not. When I put my own SIM in and switch on it asks me to "Enter PIN code" which doesn't happen if I simply remove and replace the original PIN.

Does this mean it needs unlocking, or something else?

Thanks

I tried googling it for you but the customer help pages on vodafone are down atm,but there is a scenario where a user has set a pin,so it seems to be a problem with the sim card and not the phone,until their customer help is back all I can suggest doing is giving vodafone customer services a call.Hope you get it sorted.