[Milsurplus] Dear Smart People: RS-232 Com 1

[Al Klase]

Hi Dave,

I don't know about traditional relays, but even the RS-232 USB dongles 
will happily drive a solid-state relay like THIS. 
<https://www.ebay.com/itm/5-x-HSR412L-DIP6-Photovoltaic-Solid-State-Relay-Optocouplers/183967960691?hash=item2ad5584e73:g:LBEAAOSwAABdiY9E>
(Fairchild product, you can buy them onesy-twosy from Mouser if you 
prefer.)  Input is an LED, so observe polarity and use a 1K series 
resistor.  Output is high voltage MOSFET's.  Will switch AC or DC.  They 
can be wired either in series or parallel depending upon the load..

I've used these to key tube-type transmitters and TTY's.

Al


On 2/8/2020 1:12 PM, David Stinson wrote:
> Hello, all you folks smarter than me, especially on computers.
> Can the common RS-232 Com Port's DTR and RTS lines
> source enough current to pull-in a small 5V relay?
>
> Thanks!
>
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-- 
Al Klase – N3FRQ
Jersey City, NJ
http://www.skywaves.ar88.net/

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