JESC Overview


Better Handling and Reduced Prop Wash with RPM Filtering

Quadcopter flight performance is greatly improved by reducing motor noise in the gyro signal and by removing filter delay. Unfortunately these goals used to oppose each other: filter out more motor noise and you will get more delay.

Not any more! RPM Filtering allows Betaflight to place very narrow notch filters on the harmonics of your motors with surgical precision. Notch filters have infinite noise suppression at their center. This allows the Rpm Filter to completely remove motor noise from your FC with much less delay than we're used to.

The results are smoother and colder motors - even with bent props - and better pid loop performance due to the much reduced filter delay. The ESCs make this possible by sending the current speed of each motor at full pid loop speed to the FC where it's used to tune the filters.

Formerly this worked only with BLHeli32 ESCs. JESC enables BLHeli_S ESCs to fully support dshot signal line rpm telemetry at up to dshot 600 and 8k pid frequency. No additional wiring required.

Up to 30% Longer and Smoother Flight with 48 khz PWM

Pulse Width Modulation (PWM) is used in quads to vary the amount of power applied to the motor. Traditionally blheli_s has used 24khz pwm to do this. JESC offers 48 khz and 96 khz options. Higher pwm frequency significantly improves battery life with small motors (esp whoop size) and reduces noise.


JESC is now available on both L and H style ESCs and it's largely free: all pwm options are free on L and H ESCs and even RPM telemetry is free on L ESCs. It's only on H ESCs that we ask for a small fee to use RPM telemetry so we can continue to professionally support and develop JESC.

The JESC firmware is based on the open source project BLHeli_S and also open source. To enable dshot rpm telemetry you need to license the optional Telemetry Service. Each ESC requires one license. Purchase 4 licenses for a 4 in 1, a single one if you need to replace one single ESC. Or splurge on the 20 license discount package to equip multiple 4 in 1's.

Additional benefits:

  • Startup beeps indicate whether dshot telemetry is working between FC and ESC.
  • 24khz, 48khz and 96 khz pwm options available.
  • Full 2000 point throttle resolution using pwm dithering with all pwm frequencies.
  • Only supports dshot - not legacy protocols. This reduces the risk of motor spin-ups due to protocol detection issues and makes the firmware smaller and faster.
  • Completely configurable using the cross platform JESC-Configurator

More information:

Have questions? Check out our FAQ or visit the JESC rcgroups thread.
Ready to purchase? Checkout out Install Instructions to learn the process.