RFID = Toll

Transit = LRT

Register as Transit tester here if u r interested, tried it and it was flawless, but too bad the available stations are limited though.
http://www.touchngo.com.my/html/mobile_transit_payment.aspx

Of course, it works like a physical TnG card

Scan to go in and scan to go out, otherwise get a penalty of 3 bucks if u missed either one

If the station doesn't have the scanner, u probably gotta ask the staff at the counter for a special token

Read the FAQ on the website before proceeding for registration.

Such "penalty" already existed for like ages now with the TnG card

Trying taking public transport (mainly bus) and then not doing either one, and there goes ur 3 bucks.