Commissioning High-speed readout for the LHCb VELO Upgrade

The new Vertex Locator for LHCb, comprising a new pixel detector and readout electronics, will be installed in 2020 for data-taking in Run 3 at the LHC. The electronics centres around the "VeloPix" ASIC at the front-end operating in a triggerless readout at 40 MHz. Custom serialisers send zero-suppressed data from the VeloPix at a line rate of 5.13 Gb/s. System tests of the com- plete electronic and optical chain, along with early results from high-speed link tests at CERN are presented.