QUICK QUESTION about voltage

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03-03-2007, 10:56 PM

Dhaark

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QUICK QUESTION about voltage

How many volts am I supposed to have on PIN2 on the DB9?
I have 9.91v, is this correct or no?

THanks

03-03-2007, 11:05 PM

Arkmage

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I havn't measured it, but usually the highest seen on an rs-232 ouput is 5v. 10 volts could fry your serial port on the PC, so be careful.

03-03-2007, 11:19 PM

Dhaark

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PIN1 = 5.00v
PIN2 = 9.91v
PIN9 = 5.00v
PIN3 = 0.00v (why>????)

THese are the voltage readings I got

03-04-2007, 07:07 AM

Reverant

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If PIN2 is either one of TX,RX (the digital signals) then 9.91v might be ok since with a voltmeter you can't get an accurate voltage level from a digital signal. IIRC the correct "on" voltage for serial ports is 12V, which is very noisy resistant.

Jim