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  1. MMT
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    I have a Garmin eTrex Legend (non-USB) that I would like to use as a wired GPS with TomTom Navigator 2004 (or Navigator 5 if I wait a little while). I hacked together a serial cable to connect my 650 and eTrex, and this setup works fine in testing with Mapopolis and Vindigo. So far, so good...

    Semsons will soon be selling a cable made just for this purpose, that also powers the Treo and GPS in addition to connecting them serially. I've exchanged a couple of emails with them (they are very responsive and helpful), and today I received this in response to some questions I asked:

    "Yes, the cable will provide power to both Treo 650 and GPS receiver. One reminder, we have done testing this cable with both Mapopolis and TomTom Navigator 2004. Mapopolis works fine. However, TomTom has a problem because it does not support TTL output which Treo 650 uses."

    I replied and asked them to elaborate on this apparent incompatibility with TomTom, to which they responded:

    "We have sent our cable to PalmOne and Mapopolis for testing. PalmOne engineer has confirmed that Treo 650 and TomTom Navigator 4 can not work together through wired connection. With Treo 650, TomTom only can support BT connection."

    I assume he meant to say that he'd sent the cable to TomTom for testing, not to Mapopolis. In any case, I'd like to know if anyone is using TomTom on a 650 with a serial connection to a GPS. If so, are you making a direct connection, or are you going through a cradle such as a Seidio 2100 that has a connection for a wired GPS? Seidio themselves sell a bundle with a 650 cradle, wired GPS, and TomTom Navigator 2004. Maybe there's something special about the cradle, but I kinda doubt it.

    Any experiences or opinions are appreciated.
  2. #2  
    > PalmOne engineer has confirmed that Treo 650 and TomTom Navigator 4 can not work together through wired connection

    That's cr*p. I am using the Seidio cradle and a wired Holux GPS receiver with TomTom 2004. It works just fine.

    I believe that the Treo puts out TTL voltages. Does your hacked cable have a TTL->RS232 voltage converter? If not, then it is not a real RS232 cable and I think you are just lucky if you get it to work with a serial GPS. If it is using a TTL->RS232 voltage converter chip (a MAX232?), then you need to power it from somewhere.

    I think the issue that they are running into is one of how to power the serial port -- there is apparently a software switch that needs to be set to enable one of the 650 pins to put out power. Some serial cables assume that this is available and use it to power the TTL->RS232 conversion, and it sounds like TOMTOM doesn't enable this pin, so no power is available.

    The Seidio cradle is externally powered, so this is not an issue. I've also seen serial cables that are externally powered (w/ batteries). If these guys are making an externally powered serial cable, then it shouldn't be an issue for them either.

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