RTS/CTS (Request To Send / Clear To Send) is an optional mechanism used to reduce data collisions. It just improves the traffic management of UART communications over just a RX and TX pin. It is an additional layer of traffic control. Quite transparent to the users.

I might add that the bottom line is that IF the hardware requires CTS/RTS, you need to connect and use it. It is the hardware manufacturer that will make that decision when they design any circuit. We have no choice. :)

@@nighthawkvs One more thing, I am really confused between Matek H743 / F765 WIng and Pixhawk 1 ( same as that of yours) both running ardupilot. Which one is better and any functional differences between them.....I want to use it only for fixed wings and multi rotors.

@@umeshjadhav3326 They have a little different circuity. The H743-Wing has a CAN buss. Very useful if you want to use CAN buss servos and other CAN buss devices like the Matek M8Q-CAN GPS. You can add a larger number of them with CAN buss. One drawback is that the CAN buss doesn’t come up until the main battery is attached. So if you do use the Matek M8Q-CAN GPS it won’t start locking GPS satellites until you attach the main battery. If you use a UART type GPS, it will start connecting to satellites when you plug in the USB cable from the ground station. I like to setup my ground station at the field, attach the USB cable from the ground station to the platform and then go about unpacking and setting up the rest of my stuff while the GPS locks up satellites and settles down. It has enough power through the USB cable to power the FC and a UART type GPS, but not enough to power the motors and such. So it is safe to leave to lockup satellites while I finish setting up. When I am ready to fly, I attach the main battery, THEN disconnect the USB cable from the ground station and the FC/GPS never loses power and has been stabilizing for as long as possible in the field. You can’t do that with a CAN buss GPS. Again because the power is supplied through the main battery and not the USB cable. Other than the CAN buss the F765-Wing and the H743-Wing are VERY much alike with almost identical pinouts, BEC board configuration, and physical layout. The F765-Wing will run INav, but the H743-Wing is not yet supported. The only electronic advantage I can see is that the clock rate on the H743-Wing is 480 MHz where the F756-Wing is 216 MHz Is one better that the other? I would say, no. They are very much the same.

@@nighthawkvs but r these better than the pixhawk ? I do have a pixhawk 1, same as that of yours....

You are very welcome.

@@nighthawkvs hi my friend good video i have crossfire how do i wire it to do this please i am using a matek f765 board thanks

@@RC-um3dv Should work like this. Let me know and will will try something else if it doesn't work. kzfaq.info/get/bejne/i61kacyhucXGd58.html

@@nighthawkvs hi it does not work i get it to work on the bench but not in the air i just use the tx and rx but crossfire does not have a rts and a cts pin or output if its there i don't see or know how to get it

@@RC-um3dv Are we talking about the telemetry radios in this video?

Sorry about that

This video is still processing but watchable. I am not sure why it is processing so long. They do that sometimes. That is a good question. Seems like if they talk enough to pass parameters then they should connect Mavlink and pass data. kzfaq.info/get/bejne/jNmjo5Wbt5yyn6c.html

They are not FC specific. You can connect them to any UART on any FC that has a spare UART. You are welcome.

@@nighthawkvs Thank you, sir.

it looks like the Holybro 500mW is no long in production. I'm looking for something similar and found this RFD900A 915Mhz 3DR Radio Telemetry 1W with UART but it's not 433Mhz which I prefer. Is this brand any good? Thanks.

@@CertsUAsPilot I have been searching for years to find a good telemetry solution. I have several of the RFD900 packet radios. They work very well. But I have switched from EZ-UHF at 433 MHz to Crossfire and Dragonlink at 915 Mhz. I also am looking for SIK radios that will work. About to field test the Dragonlink and Crossfire Nano Pro solutions for telemetry.

@@nighthawkvs Thank you and have a great day.

Likely very limited range. Great for the bench, but not so much for flights. Higher power telemetry radios are better for flight.

I am flying ArduPlane before I try INav. You should setup a UART in INav for the telemetry. I have another video showing exactly how to do that. kzfaq.info/get/bejne/i61kacyhucXGd58.html The F405-Wing should work just as well as the F765-wing. Not sure about your third question. 3DR systems as in Mission Planner have the ability to change the amount of telemetry that is being sent. Trying to get too much too fast might slow Mission Planner. But that depends mostly on how good a computer is running Mission Planner. If it is a slow computer, I would suggest lowering the data rate for telemetry.

@@nighthawkvs hi! Thanks for your reply. I Check the f405. The problem is this fc does not have a Cts7 and Rts7 pin. So this will be a problem right ?

@@jeangalibert8283 I loaded up some flight controllers here and found that INav doesn't care if CTS/RTS are connected or not. I don't think it will be a problem at all.

@@nighthawkvs ok so i plug positive négative tx and rx that all?

@@jeangalibert8283 Correct. And setup a port in INav.