How long, Usb midi cable ?

[ster100]

How long may be a cable between my pc and digital piano (Usb midi cable) ?

[quantum]

Realize that these are two different types of cables. 

After digging around, it looks like the recommended max length of a full speed USB cable is 5 meters.  The recommended max length of a MIDI cable is 50 feet. 

If you have a MIDI to USB device, you need to find out what part is sending a MIDI signal and what part is sending USB.  In any case, shorter will reduce the chance of interference. 

If you need really long runs, you might want to look at a MIDI over LAN solution. 

[stevebob]

Realize that these are two different types of cables....

I believe the original poster is referring to a single cable that has MIDI in and out plugs at one end (for the digital piano) and a USB connector at the other end (for the PC).  They come in different lengths and are sold at an astounding spectrum of prices (from several dollars to many times that, in the U.S. at least).

I don't know what the practical or theoretical limit on the cable's length is, but, all things being equal, the shorter the better.  The minimum functional length (assuming the digital piano is in direct proximity to the computer) would probably be six feet.

[perfect_pitch]

How long may be a cable between my pc and digital piano (Usb midi cable) ?

Depends... How long is a piece of string???   

[keyboardclass]

Realize that these are two different types of cables. 

After digging around, it looks like the recommended max length of a full speed USB cable is 5 meters.  The recommended max length of a MIDI cable is 50 feet. 

I think you're saying it's a matter of where in the cable midi is converted to USB.  I've run extremely long midi leads but as you note I don't think USB can run as long.