16b / 18b coding for HSSG ??

[bgregory@xxxxxxxxx]

     I've heard a few people mention 16b/18b as a possible coding scheme 
     that is similar to 8b/10b but with half the overhead.  Does anyone 
     know anything about this ... any comments?  I've been trying to locate 
     any material on this coding and can't seem to find anything on the 
     internet.  
     
     Would this scheme fall under the IBM 8b/10b patent, or is it 
     controlled by another company?
     
     Regards,
     Bryan Gregory