This Twinax option part number 48924 has been replaced by G48924 in mid to late 2006 . Click here for details.
The information for the 48924 Twinax kit on this page is still valid for reference.
 

Items to note:

Space Compression

There may be instances where the printer is receiving unwanted spaces in the data or missing spaces when they are expected. This errant response may be due to Space Compression and undesired or desired responses to this capability. The Twinax option has the ability to turn compression on or off based on a strap setting on the twinax board.

Removing the jumper on the Twinax board will enable space compression interpretation. The strap is installed by default disabling space compression response at position LD1 on the pin post. (shorting the left most pins).