Yealink EXP20 Expansion Module (T27/T29)

The illumination source used behind a display panel, such as LED, WLED, CCFL or LCD. It determines the brightness, energy consumption and color accuracy of the screen.

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 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.

The Harmonized System (HS) code is a standardized numerical identifier used internationally to classify traded goods. It consists of up to six digits, where each pair of digits represents progressively more specific product categories. The HS code facilitates customs duties, trade statistics, and regulatory compliance by providing a common language for describing products across borders.

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.