HP50g - RS-232 cable

[cyrille de brébisson]

Hello,

rs232 is negative logic: signal0 means logical 1 and vice-versa.
rs232 signal levels are in the +/-3~15V range.

However, although modern CPU DO generate "serial" output with the same "shape" as rs232 did, the logic is positive and the signal level are typically in the 0-3.3V range (with 0= logical 0 and 3.3V= logical 1).

Hence the need for signal convertors.

Luckily enough, with Arduino, it is very easy to find such convertors at a low price.
https://www.amazon.fr/Sumind-D%C3%A9boga...way&sr=8-7

Cyrille