> Actually, a proper RS232 driver has a guaranteed minimum source impedence, > which would eliminate the need for the resistor. However, the resistor is > _very_ cheap insurance. Are you sure this is true for the 5V side where he hooked it up? It sounds a little odd, but I don't have the spec sheet in front of me right now. ***************************************************************** Embed Inc, embedded system specialists in Littleton Massachusetts (978) 742-9014, http://www.embedinc.com -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu