The ATLAS level-1 calorimeter trigger is a hardware-based system with the goal of identifying high-pT objects within an overall latency of 2.5 μs. It is composed of a PreProcessor system which digitises 7200 analogue channels, determines the bunchcrossing of the interaction and provides a fine timing and energy calibration; and two subsequent digital processors. The PreProcessor plays a central role during integration of the system as it provides digitisation and readout of calorimeter signals and serves as a digital signal source for the subsequent processors. In this presentation the system architecture, the board production testing, and cable installation are described. Results on commissioning efforts and signal integrity tests are presented