TT21 connectivity problem

[Ian Melville]

From the FTDI cable manual, Red LED is the Received LED, you should be seeing green if you are transmitting from the PAW to the TT21.

You seem to have wired and configured it as I would expect. Can you attach a photo of the cables in the 25-way connector? Also the label on the FTDI cable?

Note that by connecting the two cables back to back you have not proved the version of cables you have TTL or Serial. If they are both the same version it will work in crossover

[ibelmore]

Hi Ian

The flashing red concerned me too.  When I connected the PilotAware to a Computer with 2 FTDI leads the lead on the PilotAware flashed Red and the one on the Computer flashed Green and the NMEA data was sent across ok.

Pic of the Cable attached, it was ordered from Farnell.

Unfortunately I can't get to the 25 pin for a pic til next week but I am now 100% certain it is wired correctly.

Cheers
Ian

[exfirepro]

Certainly the right lead Ian. I have one here in front of me, and you have the correct colour wires for ADSB Out. Definitely something strange going on. Needs further investigation.

Regards

Peter

[ibelmore]

Thanks Peter

I think my next move is to get the units back to Trig.

Still concerned about the flashing red LED on the FTDI cable when Ian says it should be green for Tx.  Having said that it does send out the data.

Ian

[Ian Melville]

Yup, that is the correct cable. As you have proved with the back to back test that MNEA sentences are getting through to the PC terminal, I would conclude the issue is withe TT21, or the way it has been cabled at the 25 pin connector.

Don't worry about the colour of the LED. I worked in telecoms for years and always associate red with transmit and green with receive. I wonder if the manual is wrong? Need to find my FTDI cable to have a look tonight. What does matter is that it works.

[exfirepro]

Thanks Peter

I think my next move is to get the units back to Trig.

Still concerned about the flashing red LED on the FTDI cable when Ian says it should be green for Tx.  Having said that it does send out the data.

Ian

Give Trig a call. They are very good and can usually turn the units round in a few days.

I'm heading down to the airfield shortly so will check out the FTDI LED colours rather than speculate.

Regards

Peter

[ibelmore]

Thanks for all the help and advice, I will let you know the outcome.

Cheers
Ian

[Ian Melville]

Mine also flashes red on transmit. Don't have a transponder, let alone a TRIG so unable to do a comparison test

[Richard]

Ian (ibelmore)
         I'v been doing a little home work for you.....I have tried to Attach my settings for the TT21 but the file is too large can you PM me you email and I will send them on to you .... as earlier in this thread it seems your wiring is correct and the correct USB to RS 232 are being used. This is all good.
   The TT21 Version is also correct as it is the same as my TT21. and is what I updated to after sending back to Trig. (there is a newer version now but the one you have is OK)
  The Bound rate I have may be different to what you are using too. As my GPS is direct into the TT21 and not through PAW (But it should just work the same. Try different Bound Rates)
   Another little thing.... The GRD from the GPS (PAW) is connected direct to my GRD BUSS and not to pin 4 or 6

I hope this helps ?

[Richard]

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I Hope this helps

[ibelmore]

Thanks Richard

PM sent

Ian

[Giver]

Ian
 
this is what mine shows with no GPS signal and the second one with,



ivor

[Giver]

photos came out back to front but i'm sure you get the picture 

[exfirepro]

Richard / Ian,

With the exception of the GPS input (NMEA 0183) and Baud rate (both must be set to the same rate, but 9,600 as quoted by Ian previously should be fine), none of the other settings on the TT21 should be critical to getting it to transmit (though some of course would lead to 'illegal' transmissions).

The PAW settings are simply 'Transponder Trig' and the Baud Rate for the correct USB port.

Having assisted with setting up several of these units for ADSB Out via PAW, The two most common issues I have come across are...

1. Setting up the wrong USB port in PAW. The numbering is NOT as shown on the Quick Start Guide. Lookin at the PAW with the Ethernet port to the left, the USB ports are numbered:

Ethernet      1   3
     Port.       2   4

2. Misreading the pin numbering in the 25 pin connector - remember the pins are numbered from the top right looking at the BACK i.e. CABLE SIDE of the plug, NOT the connecting face.

If both of these are definitely correct Ian, I am frankly stumped.

If you still can't get it working after rechecking your wiring, let me know and I will pop down to Trig and have a chat with the technicians for you.

Regards

Peter

[ibelmore]

Ivor,

Thanks for the pics, interestingly, i only get dashes where the position should be and no warning.

I will have to look at it again next week.

Richard

Yes, definitely correct port and wiring, like you, I'm stumped.

I've had a couple of weeks away from it so I will go down next week afresh and go through it again, one last time before sending the unit back to Trig to rule that out.

Thanks again
Ian