Hi Alan, Thanks Alan for your response. I've had a hard-time yesterday looking into Microchip's web site (it's been hard to get into lately), but I plan on searching their site for any ON-CHIP DEBUGGER SPECIFICATION for the PIC18 architecture -- the only one I could find last time I searched was for the PIC1687x devices (of which I quoted in my post). Anyway, thanks again for your comments. Take care, Ken Pergola -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.