by Eric Brouwer » Fri Jan 14, 2005 7:59 pm
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.