The average second level trigger rate of 100 Hz in ZEUS allows commercial micro-processors to be implemented at this stage. Transputers are the main processors used for front-end readout, data buffering, second level triggering and data acquisition by most components.
Many components also use transputers for their monitoring.
For example, the calorimeter second level trigger uses a regular tree-type network. The calorimeter readout and event-builder implement link switches to merge event data. The central tracking detector uses the occam communication structure for merging processor data and fanning out the global second level trigger decision rather than link switches. The following is a brief description of some of the transputer arrays in the ZEUS experiment. Those transputer systems in ZEUS which are not mentioned have similar characteristics to those described here.