Wireless video sales terminal uses TransferJet for super-fast download
Toshiba has combined the high-speed wireless link TransferJet with NFC and wireless charging in a concept that it is calling a ‘digital kiosk’.
“Digital Kiosk shows a use case in which rich digital content, including HD video, can be purchased and downloaded swiftly to mobile devices, such as smartphones,” said the firm. “It shows how various emerging wireless technologies can function together to deliver new services.”
The unit has an LCD screen with platter for phone charging or wireless connection, and status LEDs.
“To operate, the user taps a kiosk app icon on their smartphone, previews the available video content via the kiosk screen, and, if decides to buy, presses the ‘purchase’ button and places the smartphone on the kiosk’s platter,” said Toshiba. “NFC authentication and payment will then initiate and, once complete, content will be downloaded via TransferJet to the phone at up to 560Mbit/s. The phones are equipped with Toshiba microUSB TransferJet dongles. Users also have the option to recharge the phone handset wirelessly on the platter.” Charging is through Qi hardware and protocols.
Although Toshiba is claiming 560Mbit/s here, actual data rate is closer to 375Mbit/s once control overheads are subtracted, according to the TransferJet industry body.
There are similarities between NFC and TransferJet, but they are radically different technologies.
Both use forms of inductive coupling, and both have their ranges limited to a few centimetres by design, however NFC has a sub-500kbit/s data rate and relies on inductive coupling between two conventional coils at 13.56MHz while TransferJet operates at 4.48GHz using an unusual antenna dubbed an ‘electric induction field coupler’.
The coupler is deliberately shaped not to produce transverse electromagnetic (TEM) waves that would propagate, but to emphasise the longitudinal component of the near magnetic field which cannot propogate.
This component is not polarised, so two similar antennas can couple whatever their orientation, but only if they are close enough.
Transmit power is tiny -70dBm/MHz max. At this level it is assumed that residual propagating waves are undetectable, therefore data is sent unencrypted.
Page 13 if this TransferJet Consortium document describes the antenna and its coupling theory in detail – see page 13.