The socket pairs represent the 26 input and outputs of the stecker board. If a double ended plug lead is connected between two socket pairs, for example K - T, then connections K and T are swapped. Note that the current passes through the stecker board twice, see the schematic diagram in C Vu 10.5. The connections from the steckerboard are connected to the entry contacts on the right face of the first wheel in normal alphabetic order in a clockwise direction. The scale engraved on the outer ring progresses clockwise.
Wheels move counter-clockwise, displaying a normal numerical progression in the windows.
The right hand wheel advances one step for each key press. The wheels move during the down stroke of the key, when the key is fully down the wheels are at their new positions. Electric current then flows from the key switch through the steckerboard, through the scrambler and is reflected back again to light one of the lamps, but never the same letter as the key, because of the nature of the reflector. The notch values given in Table 1 are the points at which a turn- over occurs. This is the point at which the left and middle wheels advance by one step for every revolution of the wheel to the right.