Logic address is a code that a visitor can press to make a call. The code must be assigned first and then associated with the physical address. The apartment number or some special codes can be used to set the logic address, which is easy for the users to remember.
there are two kinds of Keypad modules:
Keypad module A-Z module: it only support logical address pure number input.
Keypad module A-L module: it support lcombine with letter and number input..