LAVA Computer MFG STS Product Family User Manual – A01
2 Vulcan St. Toronto, ON Tel: +1 416 674-5942 www.lavalink.com
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Canada, M9W 1L2 Fax: +1 416 674-8262 Toll Free (US & Canada): 800 241-5282
Tablet Charging (SimulCharge versus Charge-Only Mode)
The tablet was originally intended as a stand-alone device. When the internal battery of the tablet requires
charging, it is plugged into a Wall/USB Charger for a period of time to restore the battery charge. The
tablet can continue to be used while being charged. Once the battery is charged, the tablet may use the
charger as a supplementary power source if the tablet is left running.
When using a Samsung Wall/USB Charger, the tablet charges at a high rate that is tablet specific. The
charge rate is also limited to the power available from the attached charger. The Samsung Wall/USB
Chargers come in a number of power ratings, each matched to the original tablet requirements.
The Samsung Wall/USB Charger is equivalent to a USB Charger with a Direct Charge Port (DCP) as
defined by the USB Battery Charging Specification R1.2. The STS** Products use the term Charge-Only
Mode to indicate the tablet battery is being charged at the highest rate permitted by tablet, and is equivalent
to a USB Charger with a Direct Charge Port (DCP).
A tablet can be plugged into a desktop (or laptop) PC, and appears as a USB Accessory to the PC. The PC
is operating as a USB Master when the tablet is attached. The PC is providing power to the tablet, but the
tablet battery is being charged at a low rate. In some cases the battery may not charge.
To plug a USB accessory into a tablet, the tablet must operate as a USB master rather than a USB
Accessory. When operating as a USB Master, the tablet is expected to supply power to the attached
accessories, which means power from the tablet battery. The USB Standard has the On-The-Go (OTG)
Host feature, in which the tablet detects that a USB accessory has been plugged in and automatically
switches to USB Host Mode.
A self-powered USB Hub can be used to offload the power required by the USB accessories from the
tablet. A self-powered USB Hub should not draw power from the USB Master, but from an alternate
supply. A self-powered USB Hub becomes the power source for the attached USB accessories.
The STS** products place the tablet into the SimulCharge Mode. SimulCharge Mode informs the tablet in
USB Host mode not to provide power for USB accessories. When SimulCharge mode is active the tablet is
expecting power to be provided to it for battery charging and running the tablet. This allows the tablet to be
run simultaneously while interacting with one or more USB accessories. Using SimulCharge Mode makes
it practical to embed a tablet in third-party enclosures and kiosks. The charging rates during SimulCharge
are specific to each tablet.
The STS** products use charging features specific to a set of Samsung tablets identified in the System
Requirements section. Simultaneous battery charging and USB Host operation are not universal among
Samsung tablets. These features are not part of the USB Battery Charging Specification.
The STS** products are expected to always be powered to keep the tablet charged, and allow operation
with USB accessories.
Note
: Charge-Only Mode is important for the Samsung Tab 4 (8” and 10.1”) operation. If the Tab 4 is
turned off, the tablet cannot be turned on or charged when SimulCharge is active. Placing the STS** in
Charge-Only Mode allows to tablet to be charged, and the option to turn it on immediately. The Tab 4 turns
itself off when the battery is allowed to run down, which results in the same problem as the tablet having
been manually turned off. This issue is unique to the Tab 4 tablet.
