> Because RS232 signaling is negative logic. That's what I used to think, but somebody corrected me many years ago.
The data is upside down but the control signals are not. >From https://en.wikipedia.org/wiki/RS-232 under Voltage levels For data transmission lines (TxD, RxD, and their secondary channel equivalents), logic one is represented as a negative voltage and the signal condition is called "mark". Logic zero is signaled with a positive voltage and the signal condition is termed "space". Control signals have the opposite polarity: the asserted or active state is positive voltage and the de-asserted or inactive state is negative voltage. Examples of control lines include request to send (RTS), clear to send (CTS), data terminal ready (DTR), and data set ready (DSR). -- These are my opinions. I hate spam. _______________________________________________ devel mailing list devel@ntpsec.org http://lists.ntpsec.org/mailman/listinfo/devel
