I use both types of output printer and pci
input is a DATAQ 4 channel and a 16 channel
Output from co2 are Millivolts per PPm
Output from ph and ppm same
Output from a voltage divider and wall powersupply plugin DC
Lamp check from a car solar cell
Relay radio shack 12 volt 15 amp
Solid stare relays used from Ebay 3-12 volt
Its all basic electric stuff , real basic
The printer port works great remember to change the computer battery out every year Xmas to new years is when I do it so I do not forget.