In order to use it you have to open C:\Users\{UserName}\Documents\My Games\Test Drive Unlimited Solar Crown\UserSetting.cfg,
Set telemetry values as follows : 

Rc2.Telemetry.TelemetryPort = 22888;
Rc2.Telemetry.TelemetryAdress = "127.0.1.1";
Rc2.Telemetry.EnableTelemetry = true;
Rc2.Telemetry.TelemetryRate = 60;

NB : 22888 must be changed according to your current simhub selected port (SimHub default being 22888).

Warning at this date the game does not provide the RPM data.
