by Yurbuh Tuggly » Mon Jul 16, 2012 6:07 am
A unit with a built-in TMC chip is best (with only the small antenna wire to plug in), but getting harder to find.
Theoretically, any GPS unit with a USB port can use an external TMC module/receiver (available many places and on-line), but universal compatibility cannot be assured. In most cases, with an external module, the module is plugged into the device USB port, and then the standard (USB-based) charger cable is plugged into the TMC module. This powers the TMC module and also the device. But again, it depends how the USB port on the device is wired internally. If the device USB port is not capable of being both for power and USB input, then it won't work. If a particular seller can recommend a particular external TMC module, then that would be the one to go with. Otherwise, it's a gamble.