talk time is the time period a battery charge will last, if one is constantly talking on the phone in a 3G cellular network.

Samsung's XCover 4 uses quite a few hardware buttons. The Android menu buttons are situated below the screen. They have a clear pressure point and make a robust impression. The standby button is on the casing's right, and the volume control and a dedicated XCover button are found on the left. Short pressure enables the flashlight, and longer pressure launches the camera. All buttons are easy to feel and have a clear pressure point. Display The display of a mobile device is characterized by its technology, resolution, pixel density, diagonal length, color depth, etc. Type/technology Front camera Modern smartphones have one or more front cameras and their positioning has led to various design concepts – pop-up camera, rotating camera, notch, punch hole, under-display camera, etc. Focal length and 35 mm equivalentLike its predecessor, the Galaxy XCover 4 is not suitable for extreme situations, but quite well-equipped for the uncertainties of everyday life. The hard shell conceals a solid, lower mid-range smartphone. One of the main characteristics of the display is its type/technology, on which depends its performance. UMTS stands for Universal Mobile Telecommunications System. Based on the GSM standard, it is deemed as a 3G mobile network standard. It has been developed by the 3GPP and its major advantage is the provision of greater bandwidth and spectral efficiency, due to the W-CDMA technology.

Information about the sensor type of the camera. Some of the most widely used types of image sensors on mobile devices are CMOS, BSI, ISOCELL, etc. Networks A mobile (cellular) network is a radio system, which allows a large number of mobile devices to communicate with each other. GSM Information about the height, i.e. the vertical side of the device when it is used in its standard orientation.Specific Absorption Rate (SAR) The SAR rating shows the amount of electromagnetic radiation absorbed by the human body when using a mobile device, expressed in W/kg. Head SAR (EU) The display resolution shows the number of pixels on the horizontal and vertical side of the screen. The higher the resolution is, the greater the detail of the displayed content. The instruction set architecture (ISA) is a set of commands used by the software to manage the CPU's work. Information about the set of instructions the processor can execute. Information about additional software and hardware features of the rear camera which improve its overall performance.

Design Information about the dimensions and weight of the device, shown in different measurement units. Body materials, available colors, certifications. Width Focal length is the distance in millimeters from the focal point of the image sensor to the optical center of the lens. The 35 mm equivalent indicates the focal length at which a full-frame camera will achieve an angle of view that's the same as the one of the camera of the mobile device. It is measured by multiplying the native focal length of the camera by the crop factor of the sensor. The crop factor itself can be determined as the ratio between the diagonal distances of the image sensor in the 35 mm camera and a given sensor. Information about the number of pixels on the horizontal and vertical dimensions of the photos taken by the front camera, indicated in megapixels as well. The device's storage configuration could be more generous, but its extensive operating system and quite useful primary camera are convincing. The input options are diverse, the screen is appropriate, and the performance sufficient for daily routine. The battery life also fits well to the good overall impression. We did not like the handset's sound quality and gaming performance as much, though.The battery type is determined by its structure and more specifically, by the chemicals used in it. There are different battery types and some of the most commonly used in mobile devices are the lithium-ion (Li-Ion) and the lithium-ion polymer battery (Li-Polymer).

The rear cameras of mobile devices use mainly a LED flash. It may arrive in a single, dual- or multi-light setup and in different arrangements. Battery The batteries of mobile devices differ in capacity and technology. They provide the electrical charge needed for the functioning of the devices. Capacity CPU is the Central Processing Unit or the processor of a mobile device. Its main function is to interpret and execute instructions contained in software applications. Even if Samsung's Galaxy XCover 4 is not quite as resistant as it appears, it is protected better than many other very sensitive smartphones. The robust plastic casing does not look bulky and even the battery can be replaced. Water and dust protection have been increased compared with the predecessor, and the speaker now functions impeccably when the handset is wet. After using it in water, we found a drop of water under the rear cover. Thus, the device should be dried separately here.The Samsung Galaxy Xcover 4 is an Android smartphone produced by Samsung Electronics and released in April 2017. It is the successor to the Samsung Galaxy Xcover 3. The Xcover 4 is waterproof and dustproof designed around the IP68 specifications. The color depth of the display is also known as bit depth. It shows the number of bits used for the color components of one pixel. Information about the maximum number of colors the screen can display. The device is also MIL-STD-810G certified, which means that in theory it should easily withstand salty air, high or low temperatures or low pressure. However, according to Wikipedia, the test conditions for consumer devices are not controlled since it is a military standard. Samsung can thus specify its own test criteria – this should be kept in mind. According to the manufacturer, the smartphone had to pass the following tests to achieve the MIL-STD 810G certification: