if connected a light to relay and then to the circuit by the parallel port can i see the status of that light?

You can't read the status of a light: it's a consumer of electricity, not a supplier.

You can read switches (and buttons which are switches that don't stay shut). You can read any device which gives an appropriate digital output. But no, you can't read a light.

You can read if it is being powered by an external source if you feed the source into the port. But I don't recommend it - if you get the voltage wrong on the source, you could fry parts of your pc. Better to use a buffer chip - look at the 74 series http://rabbit.eng.miami.edu/info/datasheets/[^] as if you get that wrong you waste a cheap IC instead!
A 74LS32 or 74HCT32 or similar should do the trick.


"thanks for ur answers
but i want my circuit without any types of ics or microships.
can i by c# know if the relay number 1 for example is on 5v stat or is 0v?
or how to know if the device is on or off?"

Suit yourself, it's your PC you are risking, not mine!

Yes you can read the status of the drive line to the relay if it is 0V or 5V.
It may be harder if you are controlling the relay from the same parallel port, though.

Have a look here[^] it may help.