Noob ? about PT's

[Mushman]

Hello
I am just getting back in to the scene and i am booked in for the next Chaddy race. I'm about to purchase a new OR s'hand personnel transponder and wanted to check first which ones work with the the clubs timing system?
It seems like these new My laps PT's, might not always be compatible.
Should i just get an old AMB or MRT?
I'm worried i might end up spending this money twice if i pull the trigger to quick on this one!
Any advice will be much appreciated.
cheers