CJ Transfer 128 is a Commodore 128 program that transfers the contents of a floppy disk to a .d64, .d71 or .d81 archive file on another computer that is connected to the C128 via a User Port RS-232 adapter and a null-modem cable. Transfer in the opposite direction is also supported. Only transfer of complete floppy disks and archive files is supported. Transfer of individual files within an archive or on a floppy disk is not supported.

The main advantage with CJ Transfer 128 is that the computer connected to the C128 can be of any type (for example PC or Amiga) and with any operating system as long as it has a serial port and a terminal program supporting the Xmodem transfer protocol. For example, HyperTerminal in Windows can be used. Many other transfer programs that exist require a PC with the MS-DOS operating system to work correctly.