The 1990s saw the coining of the phrase "cellular telephone" and its inevitable contraction "cel." We all know this word: "What's your cel number?" "Call me on my cel!" "My cel's ringing; hold on."
Some perverts, however, seem to think this contracted word, when written out, should be spelled with two Ls, as "cell," having the same spelling as the word used quite broadly to indicate closed systems with distinct boundaries in biology, electricity, architecture, entomology, and aeronautics, among others. "Cell" returns 12 significant meanings at dictionary.com, whereas "cel" returns only 1, which is the noun referring to a transparent piece of celluloid used in the graphic arts, especially animation. If only for the sake of lightening the load on "cell," it makes sense to adopt "cel" to contract "cellular telephone."
But there are other reasons. "Cell" is not a contraction of any kind of longer word when used in its pre-wireless sense. When referring to the unit of biological structure or the room for containing a prisoner, we do not imply that the term we choose is aural shorthand for a longer, multisyllabic, more difficult phrase, as we do with hold-on-my-cel-is-ringing. And the natural place to contract "cellular" is at the syllable, between the Ls, as we would when breaking the word across lines on a page. Some might argue that since "cellular" is derived from "cell" we should contract "cellular" as "cell," but that misses some subtle points of etymology. "Cellular" may be derived from "cell," but when we contract "cellular telephone" we're not making the logically reverse adjective-to-noun derivation--we're just shortening a cumbersome phrase.
What's more, "cell" already has an established meaning in the field of wireless communications, viz. the geographical area covered by an individual antenna in a "cellular network."
Finally, there's the argument from Occam's razor: "cel" uses fewer letters and thus less ink and less space on the page or screen. The extra L is "done in vain," and while force of habit and concerns regarding clarity might excuse (if not justify) its presence in the traditional uses of "cell," if we're going to coin new uses for the sound we might as well spare the extra letter and emphasize both the novelty and contractive origins of the word with "cel."