Help for ALL protocols

Xmodem        Transmits 128 byte blocks with acknowledgement after each
              block.  Available in any communications program, it is the
              slowest of all.  Use only when no other choice is available.

SEAlink       An Xmodem variant that is 15-20% faster than Xmodem.

Modem7        An Xmodem variant that is seldom used anymore.

1k-Xmodem     An Xmodem variant using 1024 byte blocks, often erroneously
              called Ymodem.  Much faster than Xmodem. Usually the
              third-best choice.

G-1k-Xmodem   A 1k-Xmodem variant, for error free channels ONLY (e.g.
              error correcting modems on both ends or direct link).
              One of the fastest protocols.  Often erroneously called
              Ymodem-G.

Ymodem        An Xmodem variant using 1024 or 128 byte blocks, which
              transmits the filename, date, and size.  Much faster than
              Xmodem.  Usually the second-best choice.

Ymodem-G      A Ymodem variant, for error free channels ONLY (e.g.
              error correcting modems on both ends or direct link).
              Much faster than Xmodem.

Zmodem        Usually the best choice, Zmodem transmits data as fast
              as possible on a non-error-free link, transmits the name,
              date, and time of the file, and changes block size as
              line conditions change.  Zmodem can resume aborted transfers
              (if your communications program is configured to do so).
              Many programs detect the host sending a Zmodem "header",
              and initiate the download without any user intervention.