base_convert
(PHP 3>= 3.0.6, PHP 4 >= 4.0.0)

base_convert -- Convert a number between arbitrary bases
Description
string base_convert ( string number, int frombase, int tobase)


Returns a string containing number represented in base tobase. The base in which number is given is specified in frombase. Both frombase and tobase have to be between 2 and 36, inclusive. Digits in numbers with a base higher than 10 will be represented with the letters a-z, with a meaning 10, b meaning 11 and z meaning 35. Example 1. base_convert()

$binary = base_convert ($hexadecimal, 16, 2);

dec2bin
bin2dec