RE: Difference between 72 PCM AND 72 PCM1024
The transmitter you have, FP-T8SSA-P, is a first generation Futaba PCM system with a resolution of 512 bits. The 1024 PCM receiver is second generation and has 1024 bit resolution and is not compatible with your transmitter. The PCM receiver you need is FP-R128DP. The system has been out of production for at least 15 years and your only chance of finding a receiver is in the RCU Classifieds or E-Bay.
I have the system and it is a very good system. It was originally intended for competition pattern flyers. Good luck in finding a receiver.
Bruce