Laptop RS232 voltages
steve_b
Posts: 1,563
Hi guys,
I'm throwing together a quick RS232 optoisolator cct and need to grab the 12V from one of the Handshake lines on the RS232 cable (CTS/RTS or something).
I measure 5.2Vdc on all the pins coming out of my IBMA31p laptop.
I know, what with all the power handling of the laptop that RS232 levels were dropped to 5V to maintain the batteries longer....but this is a pain.
I am trying to power a 5Vregulator and need at least 5V+1.7V to sustain regulation.· Can't do this when I only have 5.2V to work with.
I know I could just steal the 5V and power it that way....but who's to say that this isn't going to be plugged in to a desktop with regular RS232 levels.· Then I risk killing my IC's.
Is there a BIOS/windows option that would enable proper levels on laptops?
Just curious!
Thanks
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Steve
http://members.rogers.com/steve.brady
http://www.geocities.com/paulsopenstage
"Inside each and every one of us is our one, true authentic swing. Something we was born with. Something that's ours and ours alone. Something that can't be learned... something that's got to be remembered."
I'm throwing together a quick RS232 optoisolator cct and need to grab the 12V from one of the Handshake lines on the RS232 cable (CTS/RTS or something).
I measure 5.2Vdc on all the pins coming out of my IBMA31p laptop.
I know, what with all the power handling of the laptop that RS232 levels were dropped to 5V to maintain the batteries longer....but this is a pain.
I am trying to power a 5Vregulator and need at least 5V+1.7V to sustain regulation.· Can't do this when I only have 5.2V to work with.
I know I could just steal the 5V and power it that way....but who's to say that this isn't going to be plugged in to a desktop with regular RS232 levels.· Then I risk killing my IC's.
Is there a BIOS/windows option that would enable proper levels on laptops?
Just curious!
Thanks
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
·
Steve
http://members.rogers.com/steve.brady
http://www.geocities.com/paulsopenstage
"Inside each and every one of us is our one, true authentic swing. Something we was born with. Something that's ours and ours alone. Something that can't be learned... something that's got to be remembered."