Solution:

This unit not only pulls power from the handshaking lines, but if a power supply is used, and disconnected to allow the unit to reset and read a change in switch settings, there may be enough voltage present from the serial lines to prevent reset. To reset, disconnect the serial lines AND power. If this unit is not set to DTR handshaking instead of X-On/X-Off, no data will be released in Parallel to Serial mode UNTIL X-On is sent. The printer port control line will be BUSY until it is sent. X-On is a character value of 17 (CTL+Q) X-Off is a character value of 19 (CTL+S)