Direct PPM serial cable is easy. - Am I missing something?

[Brian Crosse]

PC serial ports are pretty dumb.

Any voltage less than about 3 volts will "read" as a "1". Any voltage higher will read as a "0". (for the techos, RS-232 to TTL inverts remember)

If the radio generates PPM at 0 to 9.6V (nominal) then you shouldn't need anything other than a solder connection to plug it in.

Why are the PIC and transistor convertion cables needed?

Is it because not all PPM outputs are 0 to 9.6V (nominal)?

Is there any other problem?

[Steve Lewin]

Let us know when you've tested this theory including the full list of radios and PCs you've tested it with. Try a JR first .

BTW PIC serial interface input to PC is nothing like the PPM encoder signal, it's a standard serial input stream.

Steve

[Brian Crosse]

The RS-232 level thing isn't so much a theory as fact. My Hitec Eclipse 7 is RS-232 level compatible.

Where the hard part is, is getting FMS to read the MSR and regenerating the data from the PPM. It seems to me that they must already have done this to get the PPM style system to work at all.

Do you know what pin (RI, DSR, CTS, DCD) is being read?

Regards,

Brian


PS Do you know how I can convince FMS to try direct port access under XP. I have set up the IOPM to allow apps to get to all ports from 0x200 to 0x3bf. FMS refuses to try!

[Steve Lewin]

Are you sure your Hitec is fully RS232 level compatible ? Try banging +/-25V or even +/-12V (RS432 ?) into it and check . I would suggest at least a resistor in the lead even if you don't want to use transistors or zener diodes to limit the damage.

Obviously TLAs and FLAs are not my thing. Why would you want FMS to read a Magnetic Stripe Reader ? Anyway, the signal is on RI for the simple serial i/f.

I have no idea what an IOPM is and have so far successfully avoided Win XP I so can't help with whatever that's about, sorry.

Good luck - Steve