In English, there are two common ways to represent the numbers zero through fifteen: in words, as I've just done, or in Arabic numerals (0, 1, 2, ... 14, 15). These numbers are used often enough with computers that a system for representing numbers in base sixteen (hexadecimal) has been been created, starting with Arabic numerals up to nine and using the first six letters of the alphabet to represent ten through fifteen.
12480 is an alphanumeric writing system designed by Bradley Tetzlaff in 2002. Any number that can be written in binary can be written in 12480. The name of 12480 "comes from the divisions of hexadecimal: 10, 8, 4, 2, 1, 0.8, 0.4, 0.2, 0.1, 0.08, etc."1 In binary, the movement of a 1 through a sequence of 0s will also give you this pattern: 0001 0010 0100 1000 0000. 12480 is written left to right, top to bottom, but this can be changed by using the baseline underline. The system was used extensively in the computer game Ecclemony.
The 12480 writing system can be classified as both a[n] alphabet and a numeral system. 12480 is based off the theory that words are only sets of a certain number of symbols with specific values. Traditional writing systems based solely on phonemes are inferior to 12480 because they cannot work both phonemically and numerically without conversion. They are often restricted to representation though phonemes and randomly selected symbols. 12480's binary basis allows it to have an optimal amount of representations using the higher base numeral systems. 12480 is far more universal than even the most common alphabet.1
12480 is a set [of] scripts and standards designed to prove that the binary numeral system, and all systems based on the squares of binary, are able to be used as writing systems for a universal language. 12480 attempts to make binary a practical writing system for the average human, rather than only for a machine.2
12480 can be expressed in many different ways. The "Main Chart" on the 12480 web site1 shows several scripts as well as assigning a consonant sound, vowel sound and a color to each value:
DC HX BN Cns Vwl Color
==========================================
0 0 0000 ħ/ʰ a black (#000000)
1 1 0001 j/ʲ i white (#FFFFFF)
2 2 0010 r/ɹ æ dark red (#800000)
3 3 0011 s ɪ dark yellow (#808000)
4 4 0100 φ/f ɛ dark green (#008000)
5 5 0101 p e dark cyan (#008080)
6 6 0110 t ʌ dark blue (#000080)
7 7 0111 k ɤ dark pink (#800080)
8 8 1000 ɣ/ˠ ɒ dark gray (#808080)
9 9 1001 w/ʷ u light gray (#E0E0E0)
10 A 1010 l/ˡ ɐ̩/ɜ red (#FF0000)
11 B 1011 ʒ ʊ yellow (#FFFF00)
12 C 1100 ð œ green (#00FF00)
13 D 1101 m ø cyan (#00FFFF)
14 E 1110 n ɔ blue (#0000FF)
15 F 1111 ŋ o pink (#FF00FF)
The sounds are represented using their IPA symbols. The numbers following each color is the HTML code for the color.
12480 scripts include the bubble script, four line script, dot script, slash script, diamond script, letter script, star script, graph script and quadnary script. Each script represents either a word or a letter by default; a list of the designations can be found at http://www.12480.8m.com/scripts.html. 12480 can also be expressed in a few styles of waveform, DNA-like encoding, tones of speech or phonemes, or on a musical staff.
The sounds may be voiced or unvoiced, but the specified sound is recommended. Notice that this writing system only has sixteen consonants and sixteen vowels. Any word that can be written in the Latin alphabet can be written in 12480, but the pronunciation may change; a conversion table is available at http://www.12480.8m.com/conversion.html.
When expressing words, it is interpreted as beginning with a consonant and then alternating between a consonant and a vowel thereafter. One-letter words are not allowed; if one is necessary the schwa sound can be tacked on the end.
Punctuation is included in the scripts, but is currently limited to a minor break (comma), moderate break (space), major break (period), colon, hyphen, slashes and brackets (also used to designate negative numbers). Other punctuation-like symbols are the six grouping symbols, capital underline (to denote proper nouns), baseline underline (to specify divisions between lines of text), letter mark (to designate a group of characters as a word), and number mark (opposite of the letter mark; also used as an integer fraction divider). There are also symbols to specify the radix of numbers (2, 4, 16 or 256).
Examples of 12480 may be found at Omniglot's 12480 page (http://www.omniglot.com/writing/12480.htm).
References:
1: The 12480 Alphanumeric Writing System: http://www.12480.8m.com/
2: Ecclemony Writing Systems: http://www.ecclemony.tekpc.net/12480.html
Muke's International Phonetic Alphabet