OKI (MSM) - 4 Megabit

M51V4260-70J
^^^---------------- M51 = OKI
M51V4260-70J
   ^--------------- V = 3,3volt / (blank) = 5volt
M51V4260-70J
    ^-------------- 1 = 16 Megabit chip
                    4 = 4  Megabit chip
M51V4260-70J
               ?--- 8 = 1K refresh
                    7 = 2K refresh
                    6 = 4K refresh
M51V4260-70J
     ^^^----------- Internal Organization: 
                    10 = 4Meg x 1
                    26 = 256K x 16
                    40 = 1Meg x 4
                    80 = 512K x 8
                    90 = 512K x 9
M51V4260-70J
       ^----------- 0 = Fast Page
                    5 = EDO
M51V4260-70J
         ^^-------- Speed: 50=50ns / 60=60ns / 70=70ns