Several common mistakes should be avoided when trying to define the digital.
(1) The first mistake is to assume that the digital is bound by the field of consumer electronics.
Focusing on consumer electronics tends to confine digitality within a relatively narrow band of history (industrial societies roughly since World War II) and a relatively small group of media objects (computers and their ilk).
(2) Another mistake is to assume that the digital means binary.
While the binary is an excellent digital technology, and binary distinction is the first digital event, any number of other digital technologies operate effectively with more than two binary tokens. The Latin Alphabet uses 26 digital tokens rather than two. The decimal integers use 10 digital tokens rather than two. A grand piano uses 88 digital tokens rather than two. In other words, the binary is not an adequate explanation for the digital; the binary itself must be explained.
(3) Likewise it is also incorrect to assume that the digital necessarily means computation.
Computation involves a mechanism that processes values or signals, given finite resources. We ought to differentiate between a type of representation and a type of calculation. The digital is a mode of mediation; it is not a mechanism, at least not immediately. And of course analog computers exist, along side digital computers. The question of the digital can never been fully explained by the answer "computer."
(4) A final error to be avoided is to assume that the digital means data or information. Indeed information may be represented digitally or analogically, depending on the case.
That said, the mere existence of a piece of information (whether digital, analog, or another mode) entails a provisional digitality, this being the just-noticed difference that demarcates a piece of information as different from its context. (Such provisional digitality--the bare fact of difference as yet unstandardized--is what I formally call "Digital 1." The event of converting provisional digitality into a regular discrete framework is called "Digital 2.")
Thus when speaking about data or information, it is important to consider two aspects, first the evidence of any form of difference whatsoever (a.k.a. just-noticed difference, or Digital 1), and second the specific mode of representation being deployed (continuous variation, discrete units, or perhaps some other mode entirely).