The IBM print-train mechanism used in the 1403 Line Printer. Different chains had different numbers of distinct characters: 48, 64, 96, and so on. The fewer distinct characters, the faster the printing speed. The 1403 had mountable print chains; user jobs could request special chains to be mounted by the operator.
Illustration: Introduction to IBM Data Processing Systems, IBM Textbook C20-1684, 1968.