PalmT3 TT3v4 eTrex Summit with a BT adaptor

[SiEvans]

Hi, I've sourced a BT rs232 adaptor and want to mount my eTrex summit in a 4x4 using the BT adaptor to send the data forward to the front of the vehicle. I can get the GPS data sent via the BT link using another application but it will not register with the TT3 software. I read that TT3 will work with any BT GPS, surely it is simply a case of recieving the data into the T3 via inbuilt BT?
Any ideas? I can send data to MS Autoroute quite happily. Does the TT3 GPS encrypt/decrypt the data? I had it hard wired but the T3 connection isn't that great when bumping about! Thanks..

[DavidW]

TomTom software doesn't use encrypted GPS or similar. Unfortunately I'm only familiar with TomTom Navigator on the Pocket PC, not the Palm OS version.

All you should need to do is select NMEA 0183v2 at whatever speed and COM port you make an outgoing connection to your Bluetooth setup from your Palm. This assumes that you have the same configurability with the Palm OS software as the Pocket PC version.



David

[SiEvans]

David, Thanks for the response. Using the Palm and the TomTom Nav app, I can configure the GPS and after 15 seconds or so, it connects with the RS 232 BT Tx, however no valid gps is detected in the TomTom app. From the Garmin website, it says the Summit is NMEA 0183 v1,2 & 3 compaitable. I have been able to use a real TomTom GPS and the app on the Palm works fine with it, however when I collect and compare the data using hyperterminal, the o/p from the Summit and TomTom is somewhat different. I am wondering now if TomTom gps sends a string to enable the application when using BT... I haven't had time to investigate it further yet. An interesting challenge! When I shut down the TomTom app on the Palm, the conection led goes out, so the link is being called and made sucessfully. An interesting development is that when I have a BT dongle on my PC, the TomTom gps links to it and displays data on the screen along ith the data from my Summit uding the RS232 adaptor - at the same time! I wasn't aware that a single BT channel could receive two signals at the same time. Any comments?

[DavidW]

It all sounds rather strange to me - though it doesn't help that I have no Palm experience whatsoever.

Multiple connections is possible - it depends on the device in question. The Emtac Trine allows four connections at once.


As for the rest - it's very hard to work it out when I don't have any Palm experience. I know how TomTom GPS behaves on the Pocket PC - but things will be different on the Palm. Maybe someone else can give you some pointers - for now, the only thing that occurs is that maybe your TomTom software is expecting to run at 38400bps, as is the standard for Bluetooth GPSes.



David

[fishd]

Sorry if this is a dumb question but have you set the Etrex Summit to output in NMEA format? The unit is advertised as NMEA compatible but not set to output NMEA strings by default.

I know with my basic Etrex that if you go to the setup screen, then interface you must choose the output to be NMEA for it to work with something like TomTom... the default protocol for Garmin GPS's is the garmin format which few applications can understand.

[SiEvans]

Hi, yes I have set the o/p to NMEA - I reeckon I've tried them all by now! I am going to see if I can decode the data from a TomTom GPS this weekend, I need to identify at what speed the TT GPS is sending its data out at. I can do this by using various serial apps and the bt usb adaptor. If it turns out to be anything other than 4800 I think I am stumped! The next step will be a patch to the TT3 software - and there's no chance of that! Thanks for the interest. Anybody know of a BT analysis tool that will give a profile of a bt signal?

[fishd]

I've just connected my TomTom bt gps to my laptop and connected to the serial port in Hyperterminal...

I get this kind of output:

[SiEvans]

Well thanks, that'll save me a trip down the road in the cold!
I'll get back to you,
Si.

[Pc-Mobile]

[SiEvans]

Hi, Yes the preference is set to BT, and the TT is set to use 'other device ' and I have tried 'TT own GPS' setting. When I set the system up, it looks for a BT client to conect to, offers up locally availble options on screen and when I select my BT adaptor, it locks on and links (switching its own link light 'on') but no data is being translated by the TT app; ie no sats or spinning black/yellow symbol. Suspecting that the TomTom GPS has a method of recognising its own brand of GPS. The extract from the TT GPS (above) is silimar to a local extract (except for the location change) so I do not see why it shouldn't work....?

[fishd]

hmm, heh... forgot about that... if anyone decodes the location information they'll get my desk at work! :D

Anyways, it is odd... I'm sure someone on here has posted about Tomtom not needing a specific GPS type although I can't remember if they were talking PocketPC or PalmOS versions, I know I've used a wired Garmin eTrex with a pals PocketPC but I don't have a cable for my Palm.

Only other thing I can think of is to get a terminal program for the palm and try to see the strings are the same on the Palm although I can't see why they wouldn't be...

Shame, I had thought about selling my TomTom GPS, buying one of those Bluetooth cables and upgrading my basic eTrex...

[SiEvans]

:D All sorted now, sorry so late in completing. The format from the etrex summit had to be units: position format: hddd.ddddd* and then it works fine, transmission is about 10 meters and the dongle supplier is nexus machines ask for smart serial port device £45+ vat del p&p etc

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