Schematic view of the TPC readout system Five SAMPA chips amplify, shape, and digitize the current signals picked up on the connected pads Two GBTx ASICs multiplex the digitized data GBTx\,0 forwards the data from two and a half SAMPA chips to a VTRx GBTx\,1 forwards the data from the other two and a half SAMPAs to one VTTx module (two optical transmit channels) GBTx\,0 also receives configuration data and the reference clock through the VTRx The reference clock is distributed to the other components A GBT-SCA chip is used for monitoring and configuration Figure taken from .