What is the difference between a DSC PK5500 / PK5501 and DSC RFK5500 / RFK5501 keypad?
Keypad part numbers can often cause issues. They all seem very similar to one another and yet the small differences do make large differences in their actual function. There are 2 main segments of the part number.
The first part is the letters: PK or RFK. The letters are kind of like a modifier. The PK in front indicates that the keypad is a standard keypad. There's no special features for that style of keypad. If there is an RFK in the front then that means that there is a wireless receiver (433 MHz) built into the keypad. This does not mean that it is a wireless keypad, it is still a hardwired keypad. But it does mean that it can receive the signal from wireless sensors and transmit those through the keybus to the PowerSeries panel. Having an RFK keypad kills two birds with one stone. This makes them very budget friendly since it is less expensive than buying a PK keypad with a separate wireless receiver module. It is also easier to install since it is one less module to get a wire run to. However, RFK keypads are not ideal for wireless reception as you have to place them in a location that is appropriate for a keypad. In most houses this is not an issue, but for larger homes or businesses or other locations that have unique environmental challenges for wireless reception you may want to get a separate module that can be placed in a more ideal location for receiving signals.
The second portion of the part number is the numbers: 5501 or 5500. These refer to the actual style of the keypad. A 5500 style keypad has a customizable alphanumeric LCD display. This allows the keypad to display a lot of information like zone labels or the event log or data in programming. A 5501 style keypad is what we call a fixed LCD screen. This keypad has a fixed set of numbers and symbols and words that can be displayed. It does not show zone labels or information in programming. Or a number of other pieces of information. These keypads work well for arming and disarming when you are on a budget, but we always tell people to get at least one 5500 style keypad to save on headaches if nothing else.