Quote: Originally Posted by Ale
I think that if the max3232 without the divider, receive data correctly, you can connect the HU to pc rs232 directly, becouse PC receiver probably is max232 or similar (I have found another EIA-232-D/V.28 driver/receiver
MC145406 that has the same threshold: "The actual turn-on input switchpoint is typically biased at 1.8V above ground, and includes 800mV of hysteresis
for noise rejection. The nominal input impedance is 5k").
And what do you think about the current drawn by that input impedance ? Is it "reasonable" to draw (in extreme case) 12V/3K = 4 mA from this signal, mainly from the point of view of the source (HU or CDC). From your experience, what would you consider the "absolutely safe maximum current" ? You see, I don't care if I fry one MAX232 or two, but I'd be really annoyed if the head unit went into smoke...
Quote:
for the connection of Txd PC-HU i'll think for a simple schematic with a transistor or a cmos buffer...
Yeah, I thought of a transistor too. I'd be happy to use one again :-)
Thanks for your help