This part is a kind of semiconductor called 82S123.

Function of this product has 256-bit TTL bipolar PROM.

Manufacturers : NXP

Image and pinout :

Some of the text within the PDF file :

Philips Semiconductors 256-bit TTL bipolar PROM (32 x 8) Product specification 82S23/82S123 DESCRIPTION The 82S23 and 82S123 are field programmable, which means that custom patterns are immediately available by following the Signetics Generic I fusing procedure. The 82S23 and 82S123 devices are supplied with all outputs at logical Low. Outputs are programmed to a logic High level at any specified address by fusing the Ni-Cr link matrix. These devices include on-chip decoding and 1 Chip Enable input for memory expansion. They feature either Open Collector or 3-State outputs for optimization of word expansion in bused organizations. Ordering information can be found on the following page. The 82S23 and 82S123 devices are also processed to military requirements for operation over the milita [ ... ]

82S123 PDF Datasheet Download