DIY USB Converter from PCMCIA Card

If you have a PCMCIA wireless internet card with a cp2102 chip on it, you can repurpose it to create a USB to serial converter board.

The cp2102 chip is highly compatible, but because it outputs TTL signals, if you need RS232, you'll also need a MAX3243CAI to convert all the serial port pins (except RI ring indicator).

For the USB port, you'll need both surface-mount and through-hole components. The serial port will use a DB9 male connector with TTL pins in the middle, which can be connected using 90-degree header pins.

PCB Manufacturing:

Once you've designed the board, solder the components onto it. Most components can be salvaged from old devices, but you'll need to purchase the MAX3243CAI, which costs about a dollar.

Completion and Setup:

Once assembled, install the drivers and your board will be ready for use. If you're not immediately using TTL, you can leave it unsoldered for now and connect it later as needed.