i need to interface between an electrical circuit and a laptop, so i can take the signal into the computer via a serial port, is there any way to do it? or any interface available in industry i can buy it to do that, cuz am looking for it till now for two weeks and still can't find it, any help would be appreciated.
You might be able to use something like an Arduino microcontroller board. It's an open-source project with easy to use hardware/software, and lots of examples. I'm not sure how you'd make it talk to another serial device, but I'm sure someone has figured it out.