From Newsgroup: comp.sys.ibm.ps2.hardware

1992_Dallas_Semiconductor_Product_Data_Book.pdf page 406

Modules with Multiplexed Address/Data Bus, cycle times of 385nS
1287 50 Bytes NV SRAM
1387 4K NV SRAM
1487 8K NV SRAM [SRAM accessed same way as 1387]

Replaces MC 146818A; MS-DOS compatible; programmable interrupts, square
wave output. DS1387, DS1397 385ns DS13XX, DS14XX, and DS15XX meet MCA
and EISA NVRAM requirements. DS1587 includes silicon serial number.

Chips with Multiplexed Address/Data Bus, cycle times of 385nS
1285 50 Bytes NV SRAM
1385 4K NV SRAM
1485 8K NV SRAM [SRAM accessed same way as 1385]

Replaces MC 146818A; MS-DOS compatible; programmable interrupts, square
wave output. DS1387, DS1397 385ns DS13XX, DS14XX, and DS15XX meet MCA
and EISA NVRAM requirements. DS1587 includes silicon serial number.
--- Synchronet 3.21a-Linux NewsLink 1.2