Hi Jim, you are correct about lower voltages on "modern" computers. Nevertheless the specs are higher and even 10-12 V is too much for most microprocessor pins. And I've seen a lot of ham shacks where *old* computers are still in use that have real serial ports with correct levels (as per sprecs). So to be on the save side we should not suggest people to apply RS-232 line levels directly even though it *might* work with some computers. ;-))
Vy 73, Olli - DH8BQA http://www.dh8bqa.de ----- Original Message ----- From: "Jim Brown" <j...@audiosystemsgroup.com> To: <elecraft@mailman.qth.net> Sent: Tuesday, March 06, 2012 6:36 AM Subject: Re: [Elecraft] Elecraft KX3 Owner's Manualnowavailable(*preliminary*) On 3/5/2012 12:58 PM, Oliver Dröse wrote: > you should*NOT* apply RTS directly to the GPIO pin! RS-232 levels go up > into the ±20 volts region per specs Not in recent recorded history! So-called RS-232 interfaces started getting cheapened many years ago (before they went away and were replaced by USB), and one of the first things to go was output voltage swing. Think about the voltages available in a laptop, for example. I'd be very surprised to see more than 10-12V on anything other than an industrial RS232 interface, and less on most laptops. 73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html ----- eMail ist virenfrei. Von AVG überprüft - www.avg.de Version: 2012.0.1913 / Virendatenbank: 2114/4852 - Ausgabedatum: 05.03.2012 ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
