sub loeschen() {
        my $f_content = $_[0];
	my $c_number = $_[1];
	my $state = "ok";

	my $pos = 0;
	my $record;

	while ( ($pos+12) < length($f_content)) {
		$record = substr($f_content,$pos+3,4);
		
		if ($record == "2500" || $record == "2800") { substr($f_content,$pos,128, ""); } # löschen funktioniert
		
		if ($record == "1500" || $record == "1800") { substr($f_content,$pos,128, 0, " " x 128); } # einfügen nicht

		$pos += 128;
	}

	return $f_content, $state;
}