Castle Creations R/C Telemetry Accessory Think of the benefits to be had from alarms that will sound to warn you when there's interference about or if your receiver battery is running unexpectedly low. Compatible castle ESC required to allow bi-directional communication protocol Compatible Radios will Support s.bus2 protocol. It is also necessary to utilize a compatible Futaba telemetry receiver. It gives the ability to transmit real-time telemetry feedback and needs to be enabled on compatible ESCs using castle Link