>Hi Folks, >I presume that it would work because of the low currents involved and the >fact that RS-232 "0" can be represented by 5V. Does this mean that a 1 is >anything less than 3V (which is what i believe the EIA Spec says). >Myke Predko The very simple, answer is "YES." This is because any non valid input voltage is defined as a logic 1 on the output.Don't become confused, this is the essential point. BUT, as Mike Fahrion pointed out, there are a some cases the negative swing is required. Something to keep in mind if it doesn't work on your friends computer. RS232 input to a pic can be through a single resistor BUT a diode to Vdd is required on at least one input, RA4 and possibly others with the 28/40-pin 16Cxx devices. Of course, this sort of interface belongs to the M2L (Mickey-Mouse logic) family and design "snobs" would never dream of using it. For many non critical applications it's ok. Keep in mind that it has poor noise immunity and may not comply with the slew rate limits of RS232. Jim