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Originally posted by Midshipman Easy@Jan 30 2003, 07:47 PM
Well in case no one has seen the new serial dell cable it is not a straight 40 pin to 9 pin cable.. it has this tiny black box between the two connectors. As it turns out it is not just there for looks! It contains a tiny chip labeled. Sipex sp3243eca ... you can read all about this chip here...
http://www.sipex.com/products/pdf/SP3223_3243E.pdf
Apperently this is how they can say that the axim has no serial port yet is still able to connect to a pc via a serial port.. really was this so hard to tell us!!!!
At any rate this nifty chip has auto on to save power when used in devices like oh say a PDA !
This is a cool feature assuming the device you connect it too can tell the chip its there !
So the mystery of why the rs232 line monitor did not light up when connected alone but then connected to the extrenal modem lit up like a christmas tree!!!
Sad news for my stowaway convertor ! Since it cant tell the chip to turn on directly this goes from being an easy thing to a bit more complicated.
Anyone reading this have an idea of how i can trick the device to be on ?.. either thru a button battery on the connector OR via software and sending a signal down to the chip to tell it turn on?
Ill keep you all updated!
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this Sipex sp3243eca is just cmos/ttl to rs232 convertor with external device autodetection.
Once AUTO ON-LINE ® function active, the device is enabled until
there is no activity on the receiver inputs. The
receiver input typically sees at least ±3V, which
are generated from the transmitters at the other
end of the cable with a ±5V minimum.
so i think you do not supply power on yout keyboard and this chip does not see and device connected.
one q from my side: could you trace the wires to and from chip to get pinouts of axim. CMOS levels are usefull too. You have chip pinouts in pdf.