XModem, YModem, and ZModem are a lineage of serial file-transfer protocols — XModem first, then YModem and ZModem improving on it with better speed, error-correction, and (in ZModem’s case) auto-start and restartable transfers. They were the standard way of pushing files down a modem or serial line in the BBS era, and that makes them just as useful for moving files onto an Atari ST over a plain null-modem cable today.
Of the three, ZModem is the one I actually use — it’s the fastest and least fiddly to get working. On the ST side that means XYZ.TTP, and on the PC side, TeraTerm’s built-in ZModem support.
Sending files back to the PC
Going the other way — ST to PC — just swaps the roles. In TeraTerm, choose Receive a file instead of Send a file, then on the ST side launch XYZ.TTP with the -u upload flag and the file to send, e.g. XYZ.TTP -u C:\MYFILE.TXT.
