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Electronics => Electronics => Topic started by: Asellith on March 10, 2010, 07:34:30 AM

Title: RS232 Switcher
Post by: Asellith on March 10, 2010, 07:34:30 AM
Ok this make sense in my head but I wanted to see if anyone saw something I might be missing. I have an old APC UPS controller that had a bunch of serial port connectors on it. They don't transmit serial data its just a db-9 connector. I want to tear out the existing circuit and mount a few relays and new connectors to create an rs232 switcher. I have several devices being tested at various times in my rack on the other side of my office. I have to check several stats on them regularly and it would save me time to be able to press a button and read the next device. I was just going to switch the connections with the relays and the theory is that it will act just like me getting up and moving the cable like I do now.

So because laziness is the mother of all invention I want to build an elaborate box to do a simple job for me :) Anyone have any thoughts on why this will not work?
Title: Re: RS232 Switcher
Post by: madsci1016 on March 10, 2010, 10:25:37 AM
Relays are noisy, hard to drive and create interference. You can easily do this with a few ICs and keep it solid state. Either a 4017 decade counter and a few transistors/mosfets, or a multiplexor ic. Don't forget about a debouncer if you use a push button.

I can't help you design a circuit at the moment, but someone good with circuits like Soeren could help you.
Title: Re: RS232 Switcher
Post by: Asellith on March 10, 2010, 01:35:46 PM
I can design the circuit but I'm not sure I have time and if its worth the effort the more I look into it. It does really only save me a little time unless I run cable all the way to my automation room to talk to the equipment in there then it could be useful but again more effort for little gain. I just VNC into stuff and talk to them that way now.