... characters.1
The control tube also holds the `present instruction' (P.I.) also known as the `actual instruction', but the behaviour of the machine can be more easily explained if we do not assume that this forms part of the `state'. Also the I.N. line can be seen to contain four characters, but two are irrelevant. 
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... one.2
This description is slightly inaccurate owing to the fact that the obeying of certain instructions lasts until after the next prepulse. But this makes no practical difference for the programmer, and when manual prepulses are used (p. [*]) the effect does not occur. 
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