ATCP
From Mudpedia
The Achaea Telnet Client Protocol was originally created and used by Achaea and the other Iron Realms muds, and later adopted by Aardwolf and Avalon, with support added to CMUD and Mudlet.
Several changes to the specification were discussed on the MudStandards forum, resulting in the creation of a new protocal called GMCP. The aforementioned muds and clients continue to support ATCP as well, in order to remain backward compatible with older implementations.
The MSDP snippet released in April 2011 by Richard Woolcock supports ATCP as a fallback option.[1]
[edit] Specification
http://www.ironrealms.com/rapture/manual/files/FeatATCP-txt.html
