Q280 In a packet exchange I see, “FF, FC, FS, FQ, EM,& YY”. What do each of of those mean?

A280 What you're seeing is a BBS forwarding exchange where the two connected systems propose transmission of messages they have available for the other user, and list which messages they wish to receive of those proposed.

For documentation of the basic F6FBB BBS proposal exchange, see:
http://www.f6fbb.org/protocole.html

For a documentation on the B2F (FC proposal) enhancements implemented by WL2K software, see: http://www.winlink.org/B2F

WL2K uses the standard FBB protocol with a B2 extension. B2 is simply a specific mechanism for encapsulating a message which allows adding attachments, addressing multiple recipients, and mixing radio and email (internet) recipients. Otherwise it is virtually identical to the FBB B1 protocol and it uses the exact same LZW compression algorithm as FBB B1. The B2 protocol (http://www.winlink.org/B2F) was developed in 1999 by the Winlink Development Team to be an efficient mechanism to move text and binary attachments using the FBB forwarding protocol. The FBB protocol and B2 is more efficient than the standard internet SMTP protocol in RF applications such as Packet or Pactor.