FCT refers to functional testing. Typically, the functional test is performed during the last phase of the production line.[1]
This is often referred to as a final quality control test, which is done to ensure that specifications are carried out by FCTs.
The process of FCTs is entailed by the emulation or simulation of the environment in which a product is expected to operate. This is done so to check, and correct any issues with functionality. The environment involved with FCTs consists of any device that communicates with an DUT, the power supply of said DUT, and any loads needed to make the DUT function correctly.
FCTs uses customer specific connectors, rather than a test point on the PCB.
Functional tests are performed in an automatic fashion by production line operators using test software. In order for this to be completed, the software will communicate with any external programmable instruments such as I/O boards, digital multimeters, and communication ports. In conjunction with the test fixture, the software that interfaces with the DUT is what makes it possible for a FCT to be performed.

Device under test (DUT), also known as equipment under test (EUT) and unit under test (UUT), is a term used to refer to a manufactured product undergoing testing, either at first manufacture or later during its life cycle as part of ongoing functional testing and calibration checks. This can include a test after repair to establish that it's performing in accordance with the original product specification.
FCT 是指功能測試，通常在生產(chǎn)線的最后階段完成，做為最終產(chǎn)品質(zhì)量控制的測試作業(yè)，保證功能規(guī)格式樣的正確執(zhí)行。DNME習(xí)慣稱為動作測試。
FCT測試過程對產(chǎn)品預(yù)期運(yùn)行環(huán)境進(jìn)行模擬，據(jù)此檢查、修正存在的功能問題。FCT涉及的環(huán)境包括與DUT通信的任何設(shè)備、DUT供電、保證DUT正常工作的所有負(fù)荷。
FCT使用用戶產(chǎn)品的連接器，不使用PCB上的測試點(diǎn)。
功能測試由生產(chǎn)線作業(yè)人員使用測試軟件自動完成, 軟件與外部可編程設(shè)備，諸如 I/O板卡、數(shù)字萬用表、通信端口等進(jìn)行通信，配合測試治具，軟件與DUT進(jìn)行交互從而完成FCT測試過程。

待測設(shè)備 (DUT)或稱為被測設(shè)備 (EUT)或稱為測試單元 (UUT)是指進(jìn)行測試的制品，可以是最初生產(chǎn)，或者產(chǎn)品生命周期中的功能測試和標(biāo)定檢驗(yàn)，還包括修理后確認(rèn)符合原始產(chǎn)品的規(guī)格式樣。

IN-CIRCUIT VS. FUNCTIONAL TEST
ICT長于：

• 定位制造缺陷，包括焊接短路、缺件、錯(cuò)件、以及斷線。
• 待測設(shè)備無需上電即可完成多項(xiàng)測試，可以避免造成設(shè)備損壞的諸多條件。
• 針床治具架與組件模型網(wǎng)絡(luò)之間對應(yīng)的測試程序編程量最小化。