Can't sleep. Did this:
This is from my old research
on the USB link to these Panasonic cordless phones we have around the house. The protocol was easy to understand, but I couldn't get the phone "talking" back in 2006. Some more reading, especially USB in a Nutshell
, cleared things up. I can retrieve the phonebook, and I can send a new phonebook.
There is no modifying the phonebook. It's up to the PC to verify and sort the entries, and send the whole thing back to the phone for any modification.
This is only the first USB device I've reverse engineered, but I suspect it's not very well designed. It's constantly (every 5-10ms) sending 16 bytes over an interrupt endpoint, with data that is never ever used, usually all zeroes. This had me confused for a while, as I was trying to read bulk data from that instead of one of the other bulk endpoints.