its called a null modem cable there are 2 so dont get the wrong one The "NULL MODEM CABLE" must have a "CROSSOVER WIRE" for flashing ps...my laptop dont have one but there are on desktops and if you are flashing the box they say on this site to use XP and not VISTA..... read the thread Digivox T get it going (UPDATED) T
most new laptops dont have a serial port so you will need to use a usb to serial adaptor and software drivers to use the null modem cable. but if you can its best to use a serial connector as usb/serial adaptor and drivers often cause more problems