On Dec 7, 2007 4:40 PM, Syd Carlin wrote: > Can someone please give me the reason why a JDM type Pic programmer designed > to be used on a PC's Serial port will not work with a Serial to USB adaptor > cable on a laptop's USB port. Because JDM type PIC programmer depend on its software programming which access serial port directly, and control the state of serial port pin so it could send programming data, clock, and programming voltage. So it is some kind of hacking. On the other hand USB to Serial port is emulation to make access to serial port available through USB port. Accessing this serial port will not have problem is the access method is true asynchronous serial communication, meaning the RXD, TXD, DTR, and RTS pin are all working as the standard protocol. When it comes to accessing the pin directly as JDM programmer do, it certainly will fail. To use USB to Serial port as programmer, you should use other type of programmer like PicStart plus, Wouter or Olin programmer. -- soliton ------------------------------------ Diskusi di http://phimega.com/forums -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist