thank you very much for your suggestions. Appreciat this very much
This circuit connects to multiple PC/servers and can read the powe LED status and control the reset and power button functions. Therefor it uses the mainboard front panel connectors.
To keep things tidy at this this stage of development i only drawed one connection from the multiplexers.
The HC595 is for the reset- and power-button emulation. I replaced the optocoupler with a triac optocoupler. So the polarity of the connection to the PC isn't important anymore. There is no need for a third connection as the power/reset function is achieved by a simple shortconnection of the two connectors.
I changed the voltage to 5V now and added ULN2803 for the HC595 for the rare case that all PCs got a reset command at once all the LEDs would light for 1-2 seconds.
I worked throug the rest of you comments and attached a new schematic. What are your thoughts now?
all the best
monitoring_0713b.fzz (54.3 KB)