This Question is regarding the sim reader.
I want to make this circuit work. But I have a problem with the circuit. From the Serial ports 3rd pin a voltage of -12V is coming. If it is so How will the transistor work?
I can understad the reason for the senor Diade placed there but if -12 is coming will the tr get biased? I tried to build this cicuit on a vero board but didnot work out. I found that tr is not biasing. The reason I guess is that the 3rd pin of the RS232 outs -12V.
Please help me to make the circuit work.