Here are a few steps that have to be taken when developing a USB peripheral to give you an idea if USB interface fits your application. To implement USB interface you must have the following:
ü Minimum PC Requirements
ü Under 127 peripherals and/or hubs
ü Speed
ü Work requirements

Minimum PC Requirements
To interface with USB, you must have a PC that can use the interface. The PC must not only have hardware but software support. The hardware support consists of a USB host controller and a root hub. The USB host controller formats the data for transition on the bus and translates the information coming off the bus into a format the PC OS can interpret. The root hub is merely a point of one or more connectors that attach a device. The root hub carries out requests from the host controller and passes data between devices. Keep in mind that only Windows OS releases of 98 and up support USB.

Under 127 peripherals
An individual USB bus can not exceed 16 feet but you may cascade as many as 5 external hubs in series. This will allow you to connect 127 peripherals and hubs, including the root hub. Keep in mind that it may be unwise to have this many devices sharing one data path. Only one device can communicate at a time. For more bandwidth you must add more data paths.

Speed
USB has three different speeds: low speed, full speed, and high speed. Bus speeds for low, full, and high speeds are 1.5M, 12M, and 480M (USB 2.0 only) respectively. The bus speed is not the data transfer speed. Bits are required for identifying, synchronizing, and error-checking. At full speed the theoretical maximum transfers are 1.216 MBps at full speed and 53.248 MBps at high speed.

Work Requirements
A USB peripheral must have a controller chip with USB interface, and code in that peripheral to carry out the USB communications. There must also be device-driver software on the host to facilitate communications with the peripheral. If the peripheral is not of a standard type the host must also have application software to enable users to access the peripheral.