  The CMS collaboration is building a new inner tracking pixel detector for the
High-Luminosity LHC. Each pixel readout chip will be controlled with a single
serial input stream at 160 Mbps and will send out data via four current mode
logic (CML) 1.28 Gbps outputs. The readout chips will be grouped in modules and
connected with up to 1.6 meters long low-mass electrical links to Low-Power
Gigabit Transceivers (lpGBT) and Versatile Link PLUS Transceiver (VTRx+)
modules that send the data optically to off-detector electronics at 10 Gbps.
The characterization of these components and system tests of the readout chain
are presented.
