arriane posted:
I need to read a 12v pulse from a serial port, Can I connect that 12V
pulse directly to the serial cable (Receive pin) and get information
from there?
Probably, yes, but.....
The direct connections between two "RS232" equipments with the Send Data of
each connected to the Recive Data of the other is called a "Null Modem."
I am aware of two different "RS232" specs, however.
One, is the RS232 recommended standard (thus the RS prefix), and its interface
is at +and - 12V. This has always been accepted as a Standard.
The other is the ANSI/EIA 232, which IS an industry Standard, and its interface
is at + and - 5V.
I've mixed the two occasionally with trouble free results, but I usually use a
pull-down resistor on the Receive Data pins to drop the voltage a bit.
Don