The Radio Shack PC-4 was used in the first movie, primarily by Dr. Spengler in the first half. It can be seen after the library scene, and during the Ghostbusters commercial. The Calculator was originally made by Casio, but, in 1983 Radio Shack and Tandy both made versions of it. (Information provided by the Vintage Calculators Forum: //www.xnumber.com/vintage_calc/)
In the film, it was mated with a TRS-80 Cassette Interface. Part Number: 26-3650.
TRS-80 Cassette Interface
The TRS-80 Cassette Interface was combined with the Radio Shack PC-4 calculator for a few scenes in the first movie. The Interface provided a means of data storage between the PC-4 model calculator and a tape recorder. Programs could also be loaded via the interface from software tapes available at that time.
based off of Part Number: 26-3651.
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