Problema con count() y substr()

[ibme74]

EL Codigo:
<?
$host = "";
$user = "";
$password = "";
$dbdat = "";
$link = mysql_connect ($host,$user,$password);
$query = "SELECT * from referen where codigo='50'";
$result=mysql_db_query($dbdat,$query,$link);
while ($row = mysql_fetch_array($result))
{
$CAMPO = $row[nombre];
$NUM_CAR = strlen($CAMPO);
$NUM_CAR_SHOW = 2;
if ($NUM_CAR > $NUM_CAR_SHOW) {
$resto = strlen ($CAMPO, 0, $NUM_CAR_SHOW);
echo "$resto" ;
echo "$NUM_CAR";
echo "juan";
echo "$NUM_CAR_SHOW" ;
}else{
echo "$CAMPO" ;
echo "$NUM_CAR ";
echo "pepe";
echo "$NUM_CAR_SHOW" ;
}
}
mysql_close();
?>

Me muestra 7juan2 , no me muestra $resto