How to read data through unknown port n functions
 

hi to all

I am getting some problem knowing how to read data, I mean wht exactly it do and wht functions it process or programming it is working on this thing. Well let me explain in simple words, it is called a taxi dispatcher n it is widely used in australian taxis. Its function is to plot d area, show incoming jobs, communicating with d base, loggin in n out n bla bla bla wht u can expect in a taxi. Well it is a bit like monitor thing with keypad on it from 0-9 n E,C,* . It got a display portion just like a calculator LCD. It is connected with its base via 15 pin D sub things. Few of the taxi drivers know tht by disconnecting a couple of wires, this dispatcher get disconnected from taxi meter and taxi GPS base. Well, because it is an electronic thing, it is programmed. I was just wondering if I could download its program and then update & upload with some few more things in it, but the problem is I dont know how to read data from this hardware. I mean if theortically we define it, connecting its 15 pin D sub pin to the computer to read data, then make changes in it, and upload it again. Take this any hardware u found in ur storeroom but u havent got the driver for it. Then u search for it, u didnt got any driver on the net as well. Then u thought to make a new one, but I am not the hardware kid, I dont know where to start from here. I know I am not good in practically viewing that, so thats why I am here to ask for help.

Please let me know any tips u got.

thank you all