What does ttyUSB mean? Sometimes, the embedded microcontroller does not come with a hardware USB interface. While it is possible to use a software-only USB stack, the additional constraints put onto the CPU and the usually small storage size often lead board designers to include a dedicated UART to USB bridge.
Because of a busy weekend I didn't really follow up other than via emails and this still hasn't been resolved. The consistent word from them was that porting a number sometimes takes 24 to 48 hours.. I spoke to a rep by phone today who promised it would be done within 2 to 4 hours.. It wasn't.
(As of 4/8/2014, the website shows that there is a charge of USD 500 and the time to create the number is 24 to 48 hours. When obtaining a DUNS number online, the wait is usually 30 business days, but assignment of a number can be immediate for UK businesses who provide their company registration number.