Implementing TMC decoder for open-source navigation system (Nokia 810)

Hi,

I am developing Python based open source navigation system for Nokia
Tablet 810
and would like to implement TMC decoder.
As there is already a number of GPS+TMC devices (bluetooth and serial
cable)
I would like to know what protocol is employed to transfer TMC
massages
with nmea sentences, to extract TMC messages from integrated GPS+TMC
broadcast.

Darius