public static String toASCIIPrintableString(byte[] tab) {
		if (tab == null) return "null";
		
		StringBuffer buf = new StringBuffer();
		
		for (int i=0; i<tab.length; i++) {
			if (tab[i] >= 0 && tab[i]<32) {
				buf.append(".");
			} else {
				buf.append((char)tab[i]);
			}
		}
		
		return buf.toString();
	}