I’m interested in making a USB to serial converter?

would it be easy or hard to design my own USB to serial converter? Is it a wrather difficult task?
a cable..that is

I take it you mean a USB to RS232 converter. Not hard. There are chips available.

http://www.pccompci.com/usb-converter/usb-converter.html

USB to Serial Port for AEM EMS / ECU / Stand Alone / Plug and Play

Samsung Bixolon SRP-350plusC Receipt Printer – Monochrome – Direct Thermal – 200 mm/s Mono – 180 dpi – USB, Serial $251.90 A high printing speed make the SRP-350plusC is one of the fastest cash desk printers in the world. Still, speed is not everything the new SRP-350plusC excels in reliability. Additionally, the printer can print vouchers and receipts in high quality….

Usb/usb Symbol Mug $9.99 New 11 ounce ceramic coffee cup with usb symbol seen on both sides Dishwasher safe…

USB memory stick Photo Mugs USB memory stick for storing and transferringelectronic data between computers…..

Pharos REC20 GPS Receiver Only $24.99 12 parallel channels. Built-in antenna. Bluetooth transceiver for wireless communication. 6-hour replaceable, rechargeable Lithium Polymer battery. Enhanced sensitivity receiver offers fast position acquisition time. Blue LED Indicator Glows blue when powered on. NMEA-0183 data protocol. Superior navigation performance in urban, canyon and foliage environments. Rigid shock and vibration compliant….

Gotta Love for You $47.41 Full Intention and Serial Diva Re-mixes….

Smarthome 2413U PowerLinc Modem INSTEON Dual-Band USB Interface, White $79.16 The USB INSTEON PowerLinc Modem is a serial-based home automation interface that allows PC- and hardware-based automation controllers to control INSTEON-compatible lights, appliances, heating/air conditioning systems and alarm systems directly via the INS…

Micro Maestro 6-channel USB Servo Controller $19.95 The six-channel Micro Maestro raises the performance bar for serial servo controllers with features such as a native USB interface and internal scripting control. Whether you want high-performance servo control (0.25?s resolution with built-in speed and acceleration control) or a general I/O controller (e.g. to interface with a sensor or ESC via your USB port), this tiny, versatile device will del…

Paladin 1577 PC Cable-Check Pro PC/LAN/Phone Patch Cable Tester $144.99 This new universal tester maps cables, detects good connections, opens, shorts or crosses. It works with over 20 types of cables including: LAN & telephone, Serial, coaxial, USB, VGA, Mini-USB, S-video, FireWire, PS/2 keyboard & parallel printer….

Omron HJ-720ITC Pocket Pedometer with Advanced Omron Health Management Software …

Omron HEM-670IT Wrist Blood Pressure Monitor with APS (Advanced Positioning Sensor) and Advanced Omron Health Management Software $107.95 Wrist blood pressure monitors are portable, accurate and simple to use. They provide a convenient choice for those who want a second unit for away from home or who have trouble placing a cuff on their arm. The Omron HEM-670IT Wrist Blood Pressure Monitor uses Omron’s patented IntelliSense technology, which inflates the wrist cuff to the ideal level with each use and offers fast, personalized, and …

Digi Edgeport/1 USB-to-Serial Adapter $98.59 Digi Edgeport/1 USB-to-Serial Adapter

SIIG USB to Serial – Value $32.61 SIIG USB to Serial – Value

StarTech.com 2 Port Industrial USB to Serial RJ45 Adapter – Wallmount $95.04 StarTech.com 2 Port Industrial USB to Serial RJ45 Adapter – Wallmount and DIN Rail

Aten UC2324 USB to Serial Hub $123.41 Aten UC2324 USB to Serial Hub

Aten USB to Serial Cable Adapter $153.21 Aten USB to Serial Cable Adapter

StarTech.com 3 ft 1s1p USB to Serial Parallel Port Adapter Cable $42.55 StarTech.com 3 ft 1s1p USB to Serial Parallel Port Adapter Cable

StarTech.com 2 Port Industrial Wall Mountable USB to Serial Adapter H $104.98 StarTech.com 2 Port Industrial Wall Mountable USB to Serial Adapter Hub with DIN Rail Clips

CODi USB-to-Serial Adapter Cable $42.55 Plug-and-play cable connects serial peripherals to a USB portHardware can be used with computers, notebooks, PDAs, modems, digital cameras, and label printerscompact, lightweight design makes adapter cable great for traveling

Tripp Lite SmartOnline SU1000RTXL2Ua 1000VA Rackmountable/Tower UPS $708.65 Ideal power supply for any network Supports USB and serial interfacesWorks with Windows and Mac OSX operating systems

StarTech.com 3ft USB to RS232 DB9 Serial Adapter Cable – M/M $30.14 StarTech.com 3ft USB to RS232 DB9 Serial Adapter Cable – M/M