PIC18f2550 usb communication with a mobile phone

[JEC]

Hi

Im using a pic18f2550 usb port to communicate with a mobile usb....
But im having some difficulties...
Does the usb of the pic need to be in "master mode" to communicate with useb of the mobile...

The '2550 is definitely only a 'slave' chip and I'd suspect that your phone is as well.

Thus, there's no chance that they'll be able to communicate over USB with each other.