In 1944, the "Luftwaffe" introduced a plugboard switch, called the "Uhr" (clock), a small box containing a switch with 40 positions. It replaced the standard plugs. After connecting the plugs, as determined in the daily key sheet, the operator turned the switch into one of the 40 positions, each producing a different combination of plug wiring. Most of these plug connections were, unlike the default plugs, not pair-wise. In one switch position, the "Uhr" did not swap letters, but simply emulated the 13 stecker wires with plugs.