I have built and successfully used the programming device for connection to a PC
 COM port.  This is for 16C84.

Fellow PICLIST people have told me that there is an incompatibility using this
 circuit on the PIC16C54.

Can anyone out there tell/show me the modifications necessary to make this work
 for 16C54s.

I have included the schematic I made for your reference.

John Mullan

Attachment converted: wonderland:PROGRAMMER.GIF (GIFf/JVWR) (0000D337)