Can any body please tell me the difference between an NEC DTH-16D-1 and an NEC DTH-16D-2? Is it in the programming? Any tips are helpful thank you!

They are Both the Same Phone The Dash 1 or 2 is the Rev.No Program Change Needed.

Version 1's had a lot of bad hook switches. Version 2's had a lot of faulty displays. Otherwise they are the same.