USB to Serial (RS232)  Adapter USB to Serial (RS232)  Adapter Schematic

These day’s most computers and laptops don’t have the RS232 port installed so if you can only connect something trough RS232 you’re looking at a problem. This project comes in handy, and gets you out of the problem. It’s really simple, few parts are involved and if you do it with SMD parts it can be pretty small(like in the picture).

USB to Serial (RS232)  Adapter: [Link]