When Dell presents its Axim seems that device haven't serial port. After some month and many request Dell released an RS232 adapter cable.
In that cable there is a small "module" about 3cm from the Axim connector with snap together halves that can be easily opened with a small screwdriver that exposes the circuit board shown below.
The Sipex SP3243ECA chip is an "RS-232 Converter" which would indicate that the Axim does not have complete RS-232 circuitry on the motherboard.
Devices using only the Tx/Rx/Gnd connections (no hardware flow control) would not work with the Axim and this cable. Reading SP3243ECA datasheets it appears that the cable circuit is expecting voltage on the DTR line to power up the converter.
So in my opinion there are tree ways to solve that problem:
open converter small box, cut pin 23 (online, normally connected to ground) and connect it with pin 22(shutdown). The converter would be powered until cable disconnection;
modify OBD interface connecting car battery out to RS232 pin6 using a 1.5K resistor. The DSR pin6 is connected to DTR pin4 (Axim cable RS232 connector) via NULL modem adapter that enables Sipex converter. In this way you should lost interface opto-isolation
connect a battery source (a normal 9Volt battery should work) to pin4 DTR (positive) and GND (negative) of NULL modem adapter (Axim side). I use this way and it works well!
Remember: Axim cable is like a NULL Modem, pin4 DTR on RS232 cable connector is connected to DSR pin6
of Axim expansion plug. So pin4 DTR isn't an Axim output line but an input!
DISCLAIMER: I am not liable or responsible to any person or entity for any errors contained on this page, or for any special, incidental, or consequential damage caused or alleged to be caused directly or indirectly by the information contained on this page. Any application of the techniques, ideas, and suggestions on this page is at the reader's sole discretion and risk.
