Not all LCD screens on Transmitters (TXs) support temperature or voltage readings. The ones that do advertise telemetry in their specs such as the DX4s from Spektrum. And even then it requires a sensor and a special receiver (RX) module. I'm not sure that Sanwa offers telemetry.
I use a temp gun and a "dumb" radio. The Revo I got secondhand has a temp sensor/failsafe unit on it. I can't recall the brand, but I believe it's Venom.