ICT: Online test machine (in circuit test), mainly tests the simulator on the circuit board, such as resistance capacitor, etc. Some high-end test machines such as HP3070 can test complex digital circuits, and use JTAG to test some digital chips. Burn, etc...
FCT: Functional test station (function test), the main test circuit board functional parts, such as high-frequency ADA buffer program and client functions, etc. ATE: high-end test instruments (ICT FCT) can be collectively referred to as ATE (automatic test equipment)
BGA: is a form of chip packaging, the main chip pin is replaced with a small tin ball, this material is more expensive, generally there are replanting fixtures and BGA reflow repair station, there is a special temperature line.
In a general company, ICT and FCT are a test department, while BGA (bug reflow) may belong to the instruments used by the maintenance department.