Hi Paul, My RLC-1 product now is able to work from a 3 volt to 5 volt supply. see http://www.digitalnemesis.com/catalogue/ This is a complete RS232 level converter in a DB9 backshell. This is good for "one off" circuits and prototyping, if you are looking for production quantities look at the MAX3232 from Maxim or any of its clones. Cheers, Ash. --- Ashley Roll Digital Nemesis Pty Ltd www.digitalnemesis.com Mobile: +61 (0)417 705 718 > My microcontroller circuit works on +3V battery. It > needs to communicate with the COM port of the PC, > hence it needs a RS232 driver. Is there any RS232 > driver chips available that will operate in 3V? -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.