General Information
Section 1
January 2009
Digital Talking-Book Player
5
Library Guide
The
white, diamond-shaped Information
button
near the left edge of the player is used to obtain
information about the reading position, the book currently being read, and the power and battery status of the
player.
The
white, rectangular Bookmark button
near the right edge is used to insert and delete bookmarks. Once a
bookmark is set, the reading position may be returned to the bookmark by using the Previous and Next
buttons provided the bookmark navigation level has been selected with the Menu button. Pressing this button
at a previously set bookmark will remove it.
External Connectors
Headphone
A bright green, circular headphone jack is located on the right side of the player. The player accepts headphones with
a 3.5 mm (mini) ring, tip, and sleeve plug. It will also accept a mono 3.5 mm (mini) tip and sleeve connector. The
player senses the presence of a connector and disconnects the speaker audio output. This output may be used to drive
external amplified speakers or a pillow speaker.
USB host
Behind the headphone jack is a USB port. This USB port can be used for several purposes:
•
Patrons may connect Assistive Technology (AT) remote control devices to control the player. (Refer to
section 2.2.)
•
Patrons can connect commercial off-the-shelf USB flash drives
2
to play books obtained from the NLS
Internet library.
•
Repair personnel may use this port to access diagnostic information during servicing.
This USB receptacle is provided with a cover to protect it when not in use.
Battery
The battery pack comprises 6 Nickel Metal Hydride (NiMH) cells, a self resetting fuse and a 70°C thermostat for
safety, and a thermistor for end of charge detection. The nominal capacity of the battery is 2000mAH which will
provide approximately 35 hours of play time (at normal speed and normal volume settings). To preserve the service
life of the battery, a charge cycle is initiated only if the remaining capacity is estimated to have fallen to less than 75
percent of full capacity. (
Note: unlike many simple consumer devices, the battery is not recharged on application of
AC power
)
The player continually monitors the charge state of the battery pack. The battery’s self discharge
3
is estimated and is
used to modify the capacity measurement.
The player reports the remaining capacity in number of hours of play time available unless this is greater than 75% of
the full capacity in which case the player reports “greater than H hours” (where H is 75% of the number of hours that
the player can play on a fully charged battery). When the player estimates that the capacity is than half an hour, the
announcement will be “Battery Low”. If the battery pack has been depleted so that the voltage is less than 6 Volts,
and the player is powered on using battery power, the message “Battery Low, Powering Off” is played and the player
will immediately power off. Due to the uncertainty of the capacity measurement the player underestimates the actual
capacity.
2
Most but not all commercially available USB flash drives will function correctly as a DTB storage medium. NLS
maintains a list of known compatible and incompatible drives.
3
Self discharge is the loss of stored charge due to chemical reactions within the battery. The rate of self discharge
doubles for every 10
o
C rise in temperature.
