Tandy TRS-80 Model 100
A business woman, with contacts in the military allowing her to partially confirm Harry's story, has a Model 100 in her briefcase (she never uses it).
Harry picks up a phone in a public booth. A young man, thinking he has dialled his father, blurts out that he is in a nuclear silo and war has started. With minutes to spare before the missiles strike, Harry rushes to get his new girlfriend out of the city.
A business woman, with contacts in the military allowing her to partially confirm Harry's story, has a Model 100 in her briefcase (she never uses it).