Yes, the PC will talk to the PICs and PICs to PC. Never PIC2PIC. (Atleast I cant think of any reason for them to do it) I am kinda leaning towards RS485 more and more since I can add even more than 4 PICs and still keep speed (access time down) and have good noise rejection (the transient thread is still fresh ;) In this project I'll use atleast 6 PIC16F877s, and hooking them all up to the same bus would be neat. Add some bootloader code and it would be possible to upgrade all pics from one place ! Also various 485 ICs state speed of min 4Mbps ! I am not sure how that is gonna be done; from what I understand 485 is 'RS232' running on a 485 bus. I have never seen RS232 do more than 112kbps. Maybe a parallell prn (PC) interface to a PIC then the PIC's RX/TX to the bus @ 4 Mbps ??? From: "wouter van ooijen & floortje hanneman > The only 'official' way to do this (assuming you want the PC to talk to the > PICs and the PICs to the PC, not PICs to PICs) is to daisy chain the > devices -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads