Step by step, each piece of the digital system is coming to fruition for patrons. One area of major progress is the cartridge, which will house the digital book. The National Library Service for the Blind and Physically Handicapped (NLS), Library of Congress, has finalized the cartridge design and is currently preparing to contract for production. To some, designing a cartridge is a seemingly mundane manufacturing process. But designing a cartridge for blind and physically handicapped patrons is no easy task, as it requires truly unique design and testing methods. In fact, products for NLS patrons typically undergo more rigorous usability testing than most commercial consumer products.


Cartridge production is a multiphase process. Developers approach each stage of production with a strong dedication to meeting patron's needs for the cartridge. The first step is to finalize its interior design. While the cartridge's functional requirements have been determined, some internal components-such
as circuitry and software-will be defined by the manufacturer. Once
the internal components are designed, the manufacturer will build cartridge prototypes. The prototypes will then undergo testing to ensure they meet NLS specifications and that they function properly. Next the manufacturer will develop production line tooling-the metal mold that plastic is poured into to form the cartridge's casing.

Before full production begins, the manufacturer will conduct verification tests on prototypes. These tests will evaluate whether the cartridge meets requirements for mechanical tolerance, electrical specifications, and the Federal Communication Commission's requirements for electromagnetic compatibility. These evaluations ensure that each aspect of the device performs optimally for patrons that will use it. Testing will also assess whether books can be recorded to the cartridge at a predetermined speed, which will be evaluated again while titles are actually duplicated onto cartridges. This helps assure that the books read properly. Additionally the cartridge must be able to rerecord a minimum number of times and meet durability requirements, which specify the number of times it should withstand,d insertion into the player. These steps will help ensure that the cartridge meets patrons' needs.

Full production of the cartridge is slated to begin in the spring of 2008. NLS anticipates producing 17,500 cartridges in the initial run and between one to two million cartridges each year into the future. Libraries within the NLS network, as well as other organizations, will be able to buy blank cartridges to record local or specialty books for their readers. Blank cartridges will be available once full production starts.


A lot of care went into designing a cartridge that would be fully accessible to patrons. The cartridge was designed to be easily inserted into the player, especially for readers with reduced dexterity. It has beveled edges as well as a large finger hole in the corner which will make it easier to grip and load into the player. Its wedge design allows it to be inserted into the player in only one direction. It was also important to NLS that all users found the cartridge's label readable. For that reason, the label includes both braille and large print characters.

The cartridge has many other benefits that will enhance patrons' reading experience. It will deliver crisper, clearer audio quality. One cartridge will hold most titles, which adds extra convenience to the reading experience. The cartridge also plays through on one side; there's no need to flip the cartridge like one would with a cassette tape. Readers will also enjoy the cartridge's improved navigation features. Once inserted into an advanced player, the cartridge has markers that will track exactly where patrons are in the book, allowing the patron to pick up right where he or she left off.

The cartridge's compact design also offers users greater portability. Unlike bulky cassettes, the cartridge is about the size of a credit card. The device will also be more reliable, since it has no moving parts to risk breaking and repairing. Unlike cassettes, it also has no tapes to tangle.

Patrons will find the cartridge to be extremely durable. To ensure the cartridges hold up to patron use and transit, they were subjected to intense durability testing. Cartridges were exposed to extreme temperatures to confirm they would not melt, freeze, crack or become unusable. They were also dropped from varying heights onto different surfaces to verify they would not break, chip, or scratch.

The cartridge will also serve patrons longer. Since flash memory is rewritable, the cartridge can be reused many times to load new books onto it. This capability makes it very cost efficient for libraries
as well.

Patrons will enjoy the flexibility the digital book has to offer. Using a USB flash drive, users will be able to download books onto their personal computers. They can essentially build a library of their favorite titles.

All of the digital system's features will empower patrons and take their reading experience to the next level. Patrons will ultimately get more out of the talking-book program than ever before.


The journey to produce a cartridge beneficial to all users was a long one, but essential in delivering an optimal result. Considerable time was spent to systematically design, develop, and test all the cartridge's features. The process started with a series of user-needs testing to reveal the qualities and features patrons desired most in a digital talking-book medium. User-needs tests were followed by a series of usability tests to refine cartridge models and prototypes and to test the functionality of the device. Most notably, the preliminary design review conducted in June 2006 tested the cartridge's usability, portability, and durability. The design review team examined the ease of handling and inserting the cartridge. It also reviewed the adequacy of its large print and braille labeling.

The next stage in the development process was to produce functional prototypes. These also went through usability testing in September 2006. Patrons validated the cartridge's design through numerous tests under real-world reading scenarios in homes, libraries, and retirement centers. Further usability testing was conducted in February 2007. This past spring, the cartridge's technical specifications were finalized during engineering design review and critical design review.

While the digital transition has been a lengthy process, patrons can be sure that the product will be worth the wait.

Flash Archive

Other Newsletters

Digital Talking Book (DTB) Milestones



Distribution-system implementation
Flash-cartridge production
Flash-cartridge duplication
Initial lot of DB containers and labels manufactured
Full player production


For Information on the NLS Digital Project contact:

Jean M. Moss, Digital Projects Coordinator
[email protected]  Fax: (202) 707-1690

To view the strategic business plan on the Web visit