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  1.    #1  
    Most palm PDAs support a serial connection - you just have to have the right cable. Now, does anyone know the pinout of the connector that plugs into the Treo 600? USB is the only simple way to get data into the device?
  2. #2  
    I would also be interested in a serial to T600 cable. There are several palm programs that could benefit from this. My interest is in the OBD (On Board Diagnostics) II connection to my Jeeps computer.
  3. #3  
    Look no further than http://www.pcables.com/cat1.htmlhttp://www.pcables.com/cat1.html . They have all the data cables you could want for the treo - I have one that I use with a Vernier Lab Pro and it looks to be working perfectly... As for building your own, it's not as simple as a straight pin-out... something about the fact that there are both Tx, Rx, and USB data lines requires more complicated circuitry than just straight conductor-to-conductor connections.
  4.    #4  
    Originally posted by Eteq
    Look no further than http://www.pcables.com/cat1.htmlhttp://www.pcables.com/cat1.html . They have all the data cables you could want for the treo - I have one that I use with a Vernier Lab Pro and it looks to be working perfectly... As for building your own, it's not as simple as a straight pin-out... something about the fact that there are both Tx, Rx, and USB data lines requires more complicated circuitry than just straight conductor-to-conductor connections.
    I found the serial cable but I have been looking through their development kit and I haven't seen an API for the serial port yet.
  5. #5  
    Be aware that the treo uses two TTL level signals for TX and RX. The serial cables and cradles pull power off of the host serial port to do level shifting and the inversion necessary to talk to an RS232 port. IF you are trying to do standard 3 wire interface to a peripheral it will not work unless the peripheral provides about 20mA of current on the handshaking lines.

    I made a little DB9 pass through with a 9v battery and a 430 Ohm resistor to provide current to the serial cradle.

    There are other ways to do this but that is the simplest.

    David
  6. #6  
    Bit of a warning - I'm not sure the cable works after-all... the test I did before was using a simulator, and when I actually use the cable on my Treo, it isn't working... I'm investigating the possible problems now.
  7.    #7  
    Originally posted by Eteq
    Bit of a warning - I'm not sure the cable works after-all... the test I did before was using a simulator, and when I actually use the cable on my Treo, it isn't working... I'm investigating the possible problems now.
    Thanks for the update.
  8. #8  
    How about you post exactly what you are trying to do and why and maybe we can help? Serial communications on the treo is a bit tricky, not hard but not as straightforward as the tungsten series. On my TT, you just wired up Tx, Rx, and gnd. With the treo you have to do inversion and / or level shifting. But if you have a Treo serial cable I just tested a neat work-around for talking to RS-232 peripherals that should only cost $5 in parts.

    David
  9.    #9  
    Originally posted by djs_tx
    How about you post exactly what you are trying to do and why and maybe we can help? Serial communications on the treo is a bit tricky, not hard but not as straightforward as the tungsten series. On my TT, you just wired up Tx, Rx, and gnd. With the treo you have to do inversion and / or level shifting. But if you have a Treo serial cable I just tested a neat work-around for talking to RS-232 peripherals that should only cost $5 in parts.

    David
    20mA on both the RTS and CTS lines?
  10. #10  
    yep.

    I have a little box with a male DB-9 serial plug on one side and a female DB-9 on the other. Pins 2, 3, and 5 are connected straight through (2 to 2, 3 to 3, 5 to 5). Then I connected a 9 volt battery. The negative terminal is connected to pin 5 (ground). The positive terminal is connected to a 430 Ohm resistor and then to all the empty pins on the male side. What this does is trick the treo serial cable into thinking it is connected to a powered serial port. It gets power from the 9 volt battery (the resistor limits current to about 20mA). This should work as long as you do not need the handshaking lines to make the connection. Also this will definitely work with Handspring brand serial cables but it might not work with cheap aftermarket cables. The irritating thing about this is you have to change out the 9V battery occasionally.

    There are other options open to you electrically depending on what you are trying to do and how much time and effort you want to spend.
  11.    #11  
    What are serial ports rated to draw at? I guess I could just look this up.
  12. #12  
    It is not the serial port that is drawing power but the conversion circuitry in the cable. Depending on the chipset for your serial port you can steal up to 100mA of current from a serial port. All the cable is doing is powering some flavor of RS232 transceiver like a MAX232.

    David

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