We saw a little while ago that once in SCSI communication mode, the LV-ROM player ignores any further serial communications. There is one exception to this, which is the mode change command to put the player back into serial communication mode. The routine above forces serial mode by making use of the following serial communication procedure:

Computer sends two spaces to the LV-ROM player via serial interface
LV-ROM player responds with capital A
If no response from LV-ROM player within a few milliseconds, computer must retry
Computer sends capital F to the LV-ROM player
LV-ROM player responds with capital A
If not response from LV-ROM player within a few milliseconds, computer must retry from the beginning
LV-ROM player is now in serial communications mode, which will remain until a SCSI mode change command is received

Simple enough, you might say; indeed, I might say so myself, but it isn't something I would have been likely to discover in 100 years of tinkering without reading it in the manual!

Click here to return to Domesday 2010 Communications Modes