IJAZ,

I fear this side discussion has turned into some kind of argument, which is not my intention at all. My initial comment was to have been more educational for the new ones, not the experienced hands (which having read your posts from time to time, I gather that you are). I'm sorry to have provided a link to a description that you interpreted differently than I did. Let's try this excerpt from http://www.camiresearch.com/Data_Com_Basics/RS232_standard.html

Voltages of -3v to -25v with respect to signal ground (pin 7) are considered logic '1' (the marking condition), whereas voltages of +3v to +25v are considered logic '0' (the spacing condition).

And this one from http://rebel.net/~mad/serialtutor/rs232.html, which says:

RS-232 is a standard electrical interface for serial data communications defined by the Electronic Industries Association (EIA). RS-232 actually comes in 3 different flavors (A, B, and C), each one defining a different voltage range for the on and off levels. The most commonly used variety is RS-232C, which defines a mark bit as a voltage between -3V and -12V and a space bit as a voltage between +3V and +12V.

This is all the elucidation I will offer on this issue, as I'm sure my nit-picking is getting tiresome.

Regards,

--
Dan Henry