- rand: documentation ( source)
<?php
$abc = array("A", "B", "C", "D", "E", "F", "G", "H", "I");
$num = array("1", "2", "3", "4", "5", "6", "7");
$newpass = $abc[rand(0, 9)] . $abc[rand(0, 9)] . $abc[rand(0, 9)] . $num[rand(1, 6)] . $num[rand(1, 6)] . $abc[rand(0, 9)] . $abc[rand(0, 9)] . $abc[rand(0, 9)];