RSx3 is the next evolution in the RSx series of servos. Taking the current RSx2 format and increasing the feeling with the added HCS functionality to achieve a linear feel and response. Best settings for use have also been added to the 5 model memories in each servo.
HCS (High speed Communcation System) is the new high speed communication system between the receiver to the servo. The HCS mode shortens communication time of the signal which is compressed. HCS compatible servos change the mode automatically by signal from receiver. So HCS compatible servos can use with all receivers. If you want to use the servos with HCS, please use with a HCS compatible receiver.