in the UK the service is free for RDS-TMC you just need to purchase the receiver
according to tomtom the usb receiver is compatible with 720 units..
but the one i have has a 2.5mm jack plug...
I thought it was only an antenna and was planning to reverse engineer
and make schematics for a home brew antenna
to share here with the navitotal community
unfortunately when i took mine apart.. there is an FM module inline :-(
so it will not be worth the time and effort to build one at home...
just purchase a module on fleabay ;-)