Something

        my $sql = "SELECT ports_per_slot FROM tblResNetSwitches WHERE hostname='$host'";
        my $sth = $null_dbh->prepare($sql);
        if (!defined($sth)) {
                my $str = $dbh->errstr;
                die("No sth " . $str);
        }
        if(!($sth->execute())) {
                my $str = $dbh->errstr;
                die("Couldn't Execute " . $str);
        }

        my @results = $sth->fetchrow_array;

        my $port_p_slot = $results[0];
        my $i = 0;

        while ($port > $port_p_slot) {
                $port = $port - $port_p_slot;
                $i++;
        }
        my $val = '';
        SWITCH: {
                $val = 'A', last SWITCH if $i == '0';
                $val = 'B', last SWITCH if $i == '1';
                $val = 'C', last SWITCH if $i == '2';
                $val = 'D', last SWITCH if $i == '3';
                $val = 'E', last SWITCH if $i == '4';
                $val = 'F', last SWITCH if $i == '5';
                $val = 'G', last SWITCH if $i == '6';
                $val = 'H', last SWITCH if $i == '7';
                $val = 'I', last SWITCH if $i == '8';
                $val = 'J', last SWITCH if $i == '9';
        } # End Switch on letters

        my $human_port = $val . $port;