After upgrading my computer, I have found I have been unable to transmit to the unit, so I cannot log in. It seems to be a combination of both the serial port on the computer and the level shifter you are using. While the level shifter I originally used worked on the original machine, it would not work on the new computer, nor with cheap Prolific converter (PL-2303) I bought on Ebay. It did however work with an aftermarket serial card, my understanding is that modern serial ports cheat and do not output voltages within the correct ranges to work effectively. If you are having trouble sending data to the unit, it is worth trying an older (Pentium era) machine, or getting hold of a serial card.
Unable to transmit
After upgrading my computer, I have found I have been unable to transmit to the unit, so I cannot log in. It seems to be a combination of both the serial port on the computer and the level shifter you are using. While the level shifter I originally used worked on the original machine, it would not work on the new computer, nor with cheap Prolific converter (PL-2303) I bought on Ebay. It did however work with an aftermarket serial card, my understanding is that modern serial ports cheat and do not output voltages within the correct ranges to work effectively. If you are having trouble sending data to the unit, it is worth trying an older (Pentium era) machine, or getting hold of a serial card.