Serial to USB

[neilwillis]

Hi,

I have a TX that I got with my Dragonfly D22. It comes with a lead to use, however it’s a serial and my laptop has no serial port. I purchased a USB to Serial adapter, but have had no luck using PPJoy.

Does anyone know if this will work? Or is there an alternative I can try?

Thanks

Neil

[phildc]

A serial to USB converter cable is awaiting a regular RS232 coded signal on one side, and will pass it to your system thru the USB port; into the system, it appears again as a (virtual) serial (also named COM) port.
With product like PPJ..., we are playing with the wires in a non-standard way, hoping that our hardware and software will accept this. In fact the timings of the PPM signal will be transposed to joystick info in a way that is NOT officially supported. This explains why there are so many problems with this type of solutions.
A serial to USB cable will in no way pass a signal that could give a valid interpretation.
Once again, be aware that non-standard solutions are beautiful, but may fail with a small hardware or system change.
The problems started with Win 2K and XP that handle the ports in another (but standard) way.
The only valid inputs (in the sense that they will still work tomorrow) come:
- on the game port or USB as a joystick, (*)
- on audio, sampling the PPM or PCM as it is output by the transmitter
- on serial or USB as a CODED signal ( a sort of PCM, e.g. the FMS PIC serial's) (*)

(*) needs a microcontroller-based cable.

Philippe.

[neilwillis]

Sorry to sound thick, but in English ?

[phildc]

Translating your word "English" to "non-technical language" ....

Sorry. It will not work. The "magic trick" used by PPJ... is stopped by the converter cable.

Don't come back asking why, I already explained.

[phildc]

You will find a list of possible connections in the topic
" FMS Forum » General Forums » General Discussions » radio transmiter"

Philippe.

[neilwillis]

Why? Only kidding!

I guessed it was a problem when it gets to the adapter!

Oh well.

[Eric Brouwer]

To Neilwillis (in sort of the best non-tech manner)

Most of the cables that are bundled with a kit, like the Dragonfly, does for some reason not work at all. It seems that the cables are build to have a different protocol than what is required by FMS. Some of these transmitters are also non PPM types, and will not work with the standard FMS Serial PIC interfaces. If the chopper came with a Zhen Hua tx, you can check out for the correct interface.

Furthermore, there are 2 types of serial interfaces available for FMS. The first consist a few resistors and 2 transistors - this type will NOT work at all with any Serial to USB converter. The other one has an IC (micro chip) and several other components - there are some chance to get this type to work.

I have several clients that are using Serial to USB converters to use the FMS Serial interface. Most of them are sattisfied, but it all depends on the Serial to USB converter used. Some of the converters have an internal buffer, that must first be filled up by the serial data received from the serial interface, and only when the buffer is full, is this data transfered to the PC. This can lead to a delay of up to 1 second from a stick movement to the correct reaction in FMS.

For notebook users, I reccomend the USB interfaces available, firstly because the notebooks all support USB, secondly, some serial to USB converters does not have enough power (too low a voltage) to drive the serial interface to ensure correct and stable operation of the circuitry.

[neilwillis]

Thanks for the reply. The lead i am using is

I have managed to use the TX fine with my PC at work using the serial port and PPJoy.

It seems that the setup of the TX using PPJoy does not work as per the instructions. when I start the app I cannot select what I need to. (i don’t remember off hand).

Is there anything I can buy to solve this?

Thanks

Neil