The K800i/K790 is a "block" (or "candy bar") style phone that weighs 115
grams, with its buttons operated by the
thumb. It has the "dual-front"
design common to most Sony Ericsson mobile phones since the
Sony Ericsson K700, with the back of the mobile phone designed like a digital camera and intended to be held sideways to take photographs. The central
joystick button is used for selecting options and navigating menus, with the "C" button as an undo or delete key, and the arrow-labelled button as a "back button". The two buttons labelled by white horizontal lines, known as
hotkeys or
soft keys perform the function of making decisions with only two choices. Such decisions are labelled on the phone's display. The button in between the right soft key and the "C" button acts as a shortcut key, which brings up a user-customisable
shortcut menu when pressed. The two "A/B" buttons on either side of the earpiece are used for
horizontal games support, as in the
Sony Ericsson W550/
W600. The on/off button is located on the top of the phone. The
Memory Stick Micro M2 slot is located on the left-hand side of the phone. On the right-hand side of the phone there are three keys: two for controlling
volume, skipping through tracks in the Media Player, changing radio channel, and zooming in and out when in camera mode. The third button on the right is the camera
shutter button which operates the phone's key feature, a 3.2-
megapixel Cyber-shot digital camera. In amongst the speaker at the top of the phone is a small camera used for video calls. Located next to this is the
IrDA port. The phone has a standard minimum user-available internal memory capacity of 64
MB. The external memory capacity can be extended by using a
Memory Stick Micro M2, intended to support both the camera and the
media player function of the phone. The phone can be connected to a computer for data transfer and recharging. Communication is made using either the built-in
Bluetooth wireless or the supplied
USB data cable, which connects to the phone using Sony Ericsson's proprietary
FastPort connector, which is located on the bottom of the phone. The phone can also be used as a Bluetooth or USB
GPRS/
3G modem. K800i/K790 cellphones feature full support for USB mass storage recognition. This means that there will be no need for driver installation on modern operating systems such as
Mac OS X,
Windows XP and
Linux, as the phone will be automatically recognized as an external storage device upon connection. Data retrieval also includes the ability to output files by infra-red and Bluetooth (as well as in network-transmitted messages) to other devices. Although typical of many recent Sony Ericsson devices, support for outputting files other than over the mobile network has been variable with other brands. In the calendar, a new feature is supported for recurring event notifications on a yearly basis, which the predecessor K750 lacked. The calendar is closely compatible with
Microsoft Outlook. Mac OS X v10.4.9 added support for calendar and contact syncing under
iSync 2.4. ==Variants==