You tell us! it's your design.
The flow of sections doesn't make sense though. If you simply want to operate relays from a remote keypad there are much easier ways to do it. I can see no reason why the MAX232 is used at all, it also seems rather pointless to send tones over a digital transmitter then decode them again when the digits can be sent numerically.
Based on the information you have given us, the blocks should be:
keypad => PIC16F877A => TX RX => PIC16F877A => relays
subject to the PIC being able to drive the relays itself, you normally need a current driver, either discrete transistors or something like a ULN2803.
For a small keypad you don't need a 16F877A, you can use a much smaller PIC type.
Brian.