The 16 MB 30 pin SIMM is not uncommon in the early Macintosh World. The Mac II used 30 pin SIMMs and had a theoretical maximum of 128 MB of RAM when all eight sockets were populated with 16 MB SIMMs. I write "theoretical" because I think that there were *details* until the SE/30 and IIcx came out around 1989. The IIx (later than the II, but earlier than the SE/30 and IIcx) required PAL SIMMs (not sure what these were, except they apparently had a PAL on board) to use larger capacity SIMMs. Anyway, the SE/30, IIcx and IIci all had eight SIMM sockets capable of using 16 MB 30 pin SIMMs giving a 128 MB memory capacity back in the very late 80s and early 90s. Quite a forward looking memory capacity for the day. Of course, it was years before you could actually get SIMMs with such high capacities. Later Apple Mac models with the same CPU chips were built with lower maximum RAM capacities for no apparent reason other than marketing weenies. Compare, e.g., the SE/30 and the Classic II or Color Classic. The pinout is standard. There are 12 address lines available on the 30 pin SIMM, giving a multiplexed address of 24 bits which translates to 16M addresses. Pin Name Description 1 VCC +5 VDC 2 /CAS Column Address Strobe 3 DQ0 Data 0 4 A0 Address 0 5 A1 Address 1 6 DQ1 Data 1 7 A2 Address 2 8 A3 Address 3 9 GND Ground 10 DQ2 Data 2 11 A4 Address 4 12 A5 Address 5 13 DQ3 Data 3 14 A6 Address 6 15 A7 Address 7 16 DQ4 Data 4 17 A8 Address 8 18 A9 Address 9 19 A10 Address 10 20 DQ5 Data 5 21 /WE Write Enable 22 GND Ground 23 DQ6 Data 6 24 A11 Address 11 25 DQ7 Data 7 26 QP Data Parity Out 27 /RAS Row Address Strobe 28 /CASP Something Parity ???? 29 DP Data Parity In 30 VCC +5 VDC Sets of four 30 pin 16MB SIMMs typically go for about $25 plus shipping on Ebay. Jeff Walther