The Serial Link device will allow you to communicate with Castle ESCs through the Castle Link Live protocol. This allows access to real time telemetry feedback from the ESC.
The device is capable of communicating through several serial protocols (e.g. TTL Serial, I2C, SPI). The serial protocols allow you to control the connected ESC's throttle level in real time while reading current operating conditions such as battery voltage and motor RPM. The device also has the ability to be controlled through an analog input, or can be used in a pass-through mode. The pass-through modes allow the Serial Link to receive the throttle signal from either an Analog or PPM input, and still allow an TTL Serial or I2C connection to pull real time data from the ESC.