Pre–internet, depending on the size of the store and retail chain, your cash registers might tie to a local small system which in turn talked to a central mainf

Pre–internet, depending on the size of the store and retail chain, your cash registers might tie to a local small system which in turn talked to a central mainframe (IBM, Dec, Unisys, etc) using APPC over SNA, or TCP/IP, or Decnet, or whatever Unisys used. Leased lines were not particularly fast, but did not need to be, you’re talking less than a megabyte of data at most per day.