ProRead Cabling Options

There are three methods for connecting together the serial ports on the PalmPilot and AltAcc.

Option 1 - Gender Changer and Null Modem

You can connect the AltAcc to the PalmPilot using the PalmPilot cradle and the AltAcc cable supplied by Black Sky Research. To do this by connecting the female DB-9 serial connector from the cradle to the female DB-9 connector of the AltAcc cable a male-male gender changer (Radio Shack part # 26-280A) and a null modem adapter (Radio Shack part #26-264) The null modem adapter swaps the Rx and Tx lines so that the AltAcc's transmit line is connected to the PalmPilot's receive line. This soulution requires the least amount of work but the two adapters and two cables together can be a little bulky.

Option 2 - Gender Changer and Cable Modification

This is also known as the "Taylor Method" It is similar to option 1 except instead of the null modem adapter you reverse the TX and RX lines in the AltAcc cable. The AltAcc cable has three lines; Ground, Transmit and Receive. The Ground line is the black wire so you need to swap the other two. Simply take a paper clip and depress the clips through the slot in the side of the cable housing while gently pulling on the wire. Once the lines are swapped you won't be able to use the cable for connecting the AltAcc directly to the PC anymore. If you use your PalmPilot to transfer the flight data to the PC from now one this shouldn't be much of a problem.

Option 3 - Custom Cable

This cable is the least bulky solution. It has a male DB-9 on one end to connect to the PalmPilot cradle and a Molex Waldom connector on the other end to connect to the AltAcc. To make this cable yourself you will need the following parts:

The parts from Digikey may be inconvenient to obtain. Digikey has a minimum order policy of $25 and the parts you need are only about $3.

Wire the cable as follows. Use the pin designations given for the AltAcc in order to get your bearings for the Waldom connector. The Pins on the Dsub connector should be marked.

You can use any three of the wires in the phone cable for this but the color convention is given above.

All of the above solutions use the PalmPilot cradle but the cradle is a little bulky. 3COM also sells a HotSync cable (part number is 10104U) which is more portable.

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