of those measurements. Prior to CASA, air shower arrays were typically modest in size, typically consisting of 50-100 detectors covering an area of around 50,000 square meters. The plan for CASA was to build a much more sensitive experiment that would be much larger in size, use state-of-the-art electronics, and be coupled with a large array of muon detectors (MIA). The expectation was that showers initiated by gamma rays would contain far fewer muons compared to showers initiated by cosmic rays. The original plan was for an array of 1064 detectors, but the number was subsequently increased to 1089. Some of the key design features CASA-MIA were the following: 1089 scintillation detectors, spread out on a square grid of 33 x 33 detectors, with a detector spacing of 15 m, covering a total area of 230,000 square meters. A CASA detector consisted of four separate scintillation counters; each counter consisted of a piece of acrylic scintillator 61 cm x 61 cm x 1.27 cm in size and read out by a single photomultiplier tube (PMT, either Amperex 2212 or EMI 9256). Each CASA detector contained a local high voltage module and a custom-made electronics board that allowed each detector to take data independently of other detectors. The CASA detectors were connected to a central controller via a rib-spine network consisting of coaxial cables with three functions: trigger request, trigger acknowledge and Ethernet. The muon array (MIA) consisted of 1024 scintillation counters, each of size 1.9 m x 1.3 m. The muon counters were arranged in 16 patches of 64 counters each and were buried beneath 3 m below the surface. Signals from the MIA counters were run under the ground to a central trailer where relative arrival times were measured by conventional LeCroy 4290 time-to-digital converters (TDCs). The trigger and data-acquisition sequence for CASA was complex because of the distributed electronics; it worked as follows: The PMT signals in each counter are each sampled by a low-level and high-level discriminator. The low discriminator level is set to around 0.1 of the signal from a typical minimum-ionizing particle; the high discriminator level is set to around three times that of the low level. A detector with two or more counters firing the high-level discriminator in 30 nsec is "alerted"; a detector with three or more counters firing the high-level discriminator if 30 nsec is "triggered. Alerted stations carry out local data