# \[Question\] Pixracer - FrSky Telemetry S.Port - How to connect? **URL:** \ **Category:** PX4 Autopilot\ **Created:** [August 6, 2016, 12:31pm UTC](https://discuss.px4.io/t/question-pixracer-frsky-telemetry-s-port-how-to-connect/860 "2016-08-06T12:31:13Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![smoak](https://discuss.px4.io/letter_avatar_proxy/v4/letter/s/b9e5f3/32.png) [@smoak](https://discuss.px4.io/u/smoak)\ **Post date:** [August 6, 2016, 12:31pm UTC](https://discuss.px4.io/t/question-pixracer-frsky-telemetry-s-port-how-to-connect/860/1 "2016-08-06T12:31:13Z")
Hi Everyone, i hope someone can validate that my wireing is correct, i can’t get S.Port to work. I’ve read the the RX should be powered by the FrFky-In but it does not seam to be the case. [http://px4.io/docs/frsky-telemetry/](http://px4.io/docs/frsky-telemetry/) If I connect the Power-Lines (red onces - see picture - just now not connected) the RX powers up and binds to my Taranis. But in any case the Pixracer does not recognize it (QGround Control shows 0 Channels). Can somebody point me in the right direction ? Image: [https://goo.gl/photos/4Y3m7X2Ysbu5mpRr9](https://goo.gl/photos/4Y3m7X2Ysbu5mpRr9) yours Marie ---
**Author:** ![LorenzMeier](https://discuss.px4.io/user_avatar/discuss.px4.io/lorenzmeier/32/17_2.png) [@LorenzMeier](https://discuss.px4.io/u/LorenzMeier)\ **Post date:** [August 6, 2016, 9:42pm UTC](https://discuss.px4.io/t/question-pixracer-frsky-telemetry-s-port-how-to-connect/860/2 "2016-08-06T21:42:20Z")
The FrSky telemetry does not transmit the radio channels. What you have there looks like a D4R-II. You need to set the jumpers according to its manual to put it into PPM-SUM mode and then connect port 1 to the S.BUS input of Pixracer. Then you can go back to FrSky telemetry. Check that you get the system voltage on your remote. ---
**Author:** ![Mark\_Whitehorn](https://discuss.px4.io/user_avatar/discuss.px4.io/mark_whitehorn/32/3533_2.png) [@Mark\_Whitehorn](https://discuss.px4.io/u/Mark_Whitehorn)\ **Post date:** [August 7, 2016, 10:23pm UTC](https://discuss.px4.io/t/question-pixracer-frsky-telemetry-s-port-how-to-connect/860/3 "2016-08-07T22:23:36Z")
That’s an XSR receiver in the photo, and it has no configuration jumpers. The black and red wires from the XSR must be connected to GND and 5V of the Pixracer RC input cable. You can connect either the SBUS or CPPM (white or green) to the RC\_INPUT line of the Pixracer, but beware that I have had problems with the XSR’s SBUS output generating garbage after a few minutes. I’m currently using the CPPM output because of that problem. The yellow wire is the S.port bus, and it should connect to both FRSKY\_IN and FRSKY\_OUT on the Pixracer. ---
**Author:** ![Chuong\_Nguyen](https://discuss.px4.io/letter_avatar_proxy/v4/letter/c/cdc98d/32.png) [@Chuong\_Nguyen](https://discuss.px4.io/u/Chuong_Nguyen)\ **Post date:** [December 30, 2017, 4:29am UTC](https://discuss.px4.io/t/question-pixracer-frsky-telemetry-s-port-how-to-connect/860/4 "2017-12-30T04:29:35Z")
Can someone please explain why the SPORT is connected to both RX and TX of FrSky? Seem very odd. What kind of data is transporting to FrSky? If I only connects the SBUS or CPPM to RCin, will that be sufficient enough to get Radio signal? SInce we can preserver the FrSky for other Serial Sensor? Thank you. ---
**Author:** ![Mark\_Whitehorn](https://discuss.px4.io/user_avatar/discuss.px4.io/mark_whitehorn/32/3533_2.png) [@Mark\_Whitehorn](https://discuss.px4.io/u/Mark_Whitehorn)\ **Post date:** [December 30, 2017, 4:42pm UTC](https://discuss.px4.io/t/question-pixracer-frsky-telemetry-s-port-how-to-connect/860/5 "2017-12-30T16:42:56Z")
S.port telemetry is half-duplex bidirectional with both transmit and receive on the same wire, but the PX4 device driver configures the UART in normal full duplex mode with separate RX and TX pins. You might find this page interesting: [http://www.robotmaker.eu/ROBOTmaker/quadcopter-3d-proximity-sensing/frysky-s-port-interface](http://www.robotmaker.eu/ROBOTmaker/quadcopter-3d-proximity-sensing/frysky-s-port-interface)