I created a client for PIC16f877 microcontroller.It is equivalent to version 20 of MRLcomm.ino.  With this client can connect to the MRL and write / read ports .. Ports A and E selected as inputs. Ports B, C and D outputs. It can improve but for now my serves me. PIN C6 is TX and C7 is RX. For conect MAX232 or any chip.             

                MRL-digitalwrite  ||                       MRL-digitalRead      

PIN BO   ||      1                     ||   PIN A0                   1

TO           ||                             ||   TO A5                     6

PIN D7   ||      24                   ||   PIN E0                   7

                                                ||     TO E2                   9       

This folder have Hex and C archive of the PIC:

https://www.mediafire.com/folder/t4oxlh37yrw7h/Mrl-PIC