THE XMODEM-1K-G PROTOCOL

 This is a variation of XMODEM-1K that is meant
 for error-free channels such as error correcting modems or
 null modem cable links between two computers. It achieves
 great speed by sending blocks one after another without wait-
 ing for acknowledgement from the receiver. Because of this
 however, it can not re-send blocks in case of errors (and thus
 the need for an error-free link). If an error is detected by
 the receiver, the transfer is aborted. This protocol is still
 mistakenly called 'Ymodem-g' by many programs, but people are
 gradually moving over to the proper name.