I have had a similar problem before with other models of Argox,which were resolved with DIP Switches etc, however in this case there are no DIP switches and the unit is already in PPLA mode. If I use the Non-Argox, i.e. the Epson, one can print labels, although not in proper format, but the Printer does not stop with the Lights alternately blinking. It would seem that there is a control code from the 4POS the printer does not like in 'ARGOX' Mode.