From 324de0d12567568b5c2ef6b6e4c8babb5ff01d48 Mon Sep 17 00:00:00 2001
From: Dobrica Pavlinusic <dpavlin@rot13.org>
Date: Thu, 29 Jul 2010 14:36:20 +0200
Subject: [PATCH] document data model on rfid tags

---
 lib/RFID/Biblio/RFID501.pm | 48 ++++++++++++++++++++++++++++++++++----
 1 file changed, 44 insertions(+), 4 deletions(-)

diff --git a/lib/RFID/Biblio/RFID501.pm b/lib/RFID/Biblio/RFID501.pm
index 23464ee..333fa25 100644
--- a/lib/RFID/Biblio/RFID501.pm
+++ b/lib/RFID/Biblio/RFID501.pm
@@ -9,12 +9,51 @@ RFID::Biblio::RFID501 - RFID Standard for Libraries
 
 =head1 DESCRIPTION
 
-This module tries to decode tag format as specified in document
+This module tries to decode tag format as described in document
 
   RFID 501: RFID Standards for Libraries
 
-However, document is lacking real specification, so tag decoding
-was done to be compliant with 3M implementation
+L<http://solutions.3m.com/wps/portal/3M/en_US/3MLibrarySystems/Home/Resources/CaseStudiesAndWhitePapers/RFID501/>
+
+Goal is to be compatibile with existing 3M Alphanumeric tag format
+which, as far as I know, isn't specificed anywhere. My documentation about
+this format is available at
+
+L<http://saturn.ffzg.hr/rot13/index.cgi?hitchhikers_guide_to_rfid>
+
+=head1 Data model
+
+=head2 3M Alphanumeric tag
+
+ 0   04 is 00 tt   i [4 bit] = number of item in set	[1 .. i .. s]
+                   s [4 bit] = total items in set
+                   tt [8 bit] = item type
+
+ 1   dd dd dd dd   dd [16 bytes] = barcode data
+ 2   dd dd dd dd
+ 3   dd dd dd dd
+ 4   dd dd dd dd
+
+ 5   bb bl ll ll   b [12 bit] = branch [unsigned]
+                   l [20 bit] = library [unsigned]
+
+ 6   cc cc cc cc   c [32 bit] = custom signed integer
+
+=head2 3M Manufacturing Blank
+
+ 0   55 55 55 55
+ 1   55 55 55 55
+ 2   55 55 55 55
+ 3   55 55 55 55
+ 4   55 55 55 55
+ 5   55 55 55 55
+ 6   00 00 00 00 
+
+=head2 Generic blank
+
+ 0   00 00 00 00
+ 1   00 00 00 00
+ 2   00 00 00 00
 
 =head1 METHODS
 
@@ -53,10 +92,11 @@ sub to_hash {
 	my ( $u1, $set_item, $u2, $type, $content, $br_lib, $custom ) = unpack('C4Z16Nl>',$data);
 	my $hash = {
 		u1 => $u1,	# FIXME
-		u2 => $u2,	# FIXME
 		set => ( $set_item & 0xf0 ) >> 4,
 		total => ( $set_item & 0x0f ),
 
+		u2 => $u2,	# FIXME
+
 		type => $type,
 		type_label => $item_type->{$type},
 		content => $content,
-- 
2.20.1