System tests with the TEPX detector for the CMS Inner Tracker upgrade

The upcoming High-Luminosity Large Hadron Collider (HL-LHC) upgrade will allow the CMS experiment to collect up to ten times the integrated luminosity than that provided by the baseline program. The CMS detector will undergo significant upgrades to handle the increased data rates and harsher operational conditions expected in the HL-LHC era with its inner tracker system completely replaced. The endcap of the upgraded inner tracker, the Tracker Endcap Pixel (TEPX) sub-detector, is composed of four disks at either end. Each double disk employs four different printed circuit boards (PCBs), hosting the TEPX modules. To reduce material and cabling, the disk PCB has fewer readout data lanes in its outer rings, which is compatible with the lower hit rate in this region. In the outer rings, data from different readout chips in the same module are merged into the primary chip. In this contribution, the final design of the TEPX disk PCB is evaluated by testing the modules on different positions of the PCB. The performance of the data merging feature of the TEPX module is also compared and validated with its normal data readout scheme.