Yealink SIP-T21 E2 VoIP Phone

Indicates whether the product comes with an AC power adapter included in the package. A value of "Yes" means a charger is supplied, while "No" indicates that no charger is provided and the user must obtain one separately.

The range of alternating current voltage that an AC adapter can accept, expressed in volts (V). It specifies the minimum and maximum supply voltages compatible with the device, ensuring safe operation across different regions and power standards.

The electrical current supplied by an AC power adapter to a device, expressed in amperes (A). It indicates the maximum output current that the adapter can provide under normal operating conditions and helps users verify compatibility with devices or accessories that require a specific input current.

The electrical potential difference supplied by the AC adapter to a device, expressed in volts (V). It indicates the nominal voltage that the charger outputs and is used to match the adapter with compatible equipment.

A list of the cable types that are supplied with the product, such as USB, HDMI, VGA, DisplayPort, LAN (RJ‑45), SATA, audio or other relevant connectors.

The colour or combination of colours that a product is available in, expressed as common names such as "Black", "Silver" or comma‑separated lists like "Black, White". It indicates the visual appearance of the item for consumers.

The linear measurement of an object from front to back or top to bottom, expressed in a physical unit such as millimeters, centimeters, inches, etc. It indicates how deep the item is and can be used for fitting, compatibility, or spatial planning.

The pixel dimensions of a display or image, expressed as width by height (e.g., 1920x1080). It indicates how many pixels are used to render visual content and is commonly used for monitors, TVs, smartphones, cameras, and digital images.

Represents the total count of Ethernet LAN (RJ‑45) interfaces available on a product. The value is an integer indicating how many physical Ethernet ports are present, regardless of speed or generation.

Indicates whether the product is equipped with a front-facing camera. The value can be "Yes" or "No", representing the presence or absence of this camera.

The vertical dimension of a product measured from its lowest to highest point. It is expressed in a physical unit such as millimetres, centimetres or inches and applies to any item where height is relevant, including books, electronics, furniture and other objects.

The physical configuration or method used to secure a product, such as clamp, bolt‑through, vertical, horizontal, rack mounting, freestanding, wall mounting, or other installation approaches.

The total count of programmable buttons or keys available on a device, such as a keyboard, tablet, or controller. Each key can be assigned a custom function or shortcut by the user. The value is an integer without any unit and represents how many distinct programmable inputs the product offers.

The range of relative humidity (in percentage) within which the product is designed to operate reliably. Values are expressed as a minimum–maximum interval such as "20 - 80 %" and indicate the acceptable environmental moisture level for optimal performance.

The range of temperatures in which a product can safely operate without risk of damage or performance degradation. Values are expressed in degrees Celsius (°C) and may represent a single temperature, a minimum–maximum interval, or an average operating point.

A list of audio codecs that the product can use for transmitting or recording voice signals, such as G.711, AMR‑NB, Opus, etc. Each value represents a valid codec supported by the device’s hardware or software.

The horizontal measurement of a product, expressed in a linear unit such as millimetres or inches. It indicates how wide the item is from one side to the other and is used for sizing, fitting, and compatibility purposes.