MCCP stands for Mud Client Compression Protocol. It is implemented as a telnet option, so MCCP will nt interfere with clients that do not support it. There are two versions of MCCP, differing only in that MCCP version 1 has a bug in its implementation. The compresssed data is a zlib stream. The offical MCCP home page is http://www.randomly.org/projects/MCCP/index.html