Originally Posted by diomania
Really? I wonder what the USB port on those two players are for... hmm... must be for cosmetics.
There are at least four common configurations of USB ports on digital players. The differences are not built into the actual physical port. It is all about the circuitry and software that backs it.
One configuration of a USB port on a device represents that device to a host computer as a storage device. IOW, it makes the device (in this case a digital player) look like a big USB flash drive whose contents depends on what disc is loaded or what is on the storage in the device). This is common on portable digital players and recorders. My Clip+, My Fuze, and my Microtrack work this way.
Another configuration of a USB port represents the device to the host as an audio interface. This is less common, but is seen on some portable digital recorders. One set of devices that I know that do this are the Zoom digital recorders. They also can be configured to act like storage devices.
In the third configuration, the USB port presents the device as a host
for a storage device. This means that you can play A/V files from something like a flash drive through your AV system with the player. This is probably the most common configuration of a USB drive on a music player intended for use in a larger AV system.
In yet another configuration, the USB port acts as a host for a Wifi adaptor. This is common among blu-ray players. The software that operates the port usually only knows how to operate a very limited selection of USB WiFi adaptors, namely one sold by the same vendor as the player for a vastly inflated price.
On general purpose computers (e.g. PCs) all of these configurations can be available on the same physical port. How the port works depends on what software you are running and what you attach to it. On digital appliances such as Blu Ray players and portable players and recorders, the device's firmware is usually far more rigidly defined. Intelligent phones and portable touch pad computers form a kind of middle ground and can be more flexible than the average digital appliance, but may not be as flexible as the USB port on a general purpose computer.