4. The method of claim 3 further including the steps of: coding each of said remaining characters as a single 4-bit unit or as two 4-bit units depending on the location of the character in a table of characters.
4. The method of claim 3 further including the steps of: coding each of said remaining characters as a single 4-bit unit or as two 4-bit units depending on the location of the character in a table of characters. 5. The method of claim 4 further including the steps of: determining which character, if any, preceded the character being coded, and selecting a different table of characters depending on the value of the preceding character.