We have the RC4 Decoder, and does pick up ALL amb transponders, even the rechargeable AMBRC transponders without a hiccup.

What I did notice is, whoever makes software, must make it compliant with the new features in the new transponders, otherwise you wont get the extra benefits of RC4 transponders.

The hybrid transponders do send info on voltage and temp.. not unique car ID.

I did have our new RC4 Decoder hooked up with the serial port, using Alycat software, and it worked perfectly picking up every transponder we had that was AMB. However, MRT transponders were at a 25 to 50 percent loss in lap counts. Some MRT that were tried were a 100% loss.

The bottom line is, if you like to race, and want to have laps counted, you need to upgrade your transponders, and right now is probably the only time it will ever be this cheap. As tracks upgrade to RC4, you will need to upgrade or be left out.