  The ATLAS experiment will replace the present Small Wheel (SW) detector with
a New Small Wheel detector (NSW) aiming to improve the performance of muon
triggering and precision tracking in the endcap region at the High-Luminosity
LHC. Small-strip Thin Gap Chamber (sTGC) is one of the two new detector
technologies used in this upgrade. A few custom-designed ASICs are needed for
the sTGC detector. We designed an sTGC ASIC interface board to test
ASIC-to-ASIC communication and validate the functionality of the entire system.
A test platform with the final readout system is set up and the whole sTGC
readout chain is demonstrated for the first time. Key parameters in the readout
chain are discussed and the results are shown.
