 The model used on the VC10 Simulator was a 3520B, this meant that it had (20)kWords of memory and a (B)acking Store.Redifon also used the 350 on the Air Canada DC9 flight simulator that was installed in Montreal in the Spring of 1966.The 350's were delivered in the 1967 to 1969 timeframe.The design of the Argus 400 started at the same time as the Argus 300.