DEC PDP-11/45

DEC PDP-11/45 (built 1972)

S/N 6583 (left), S/N 5270 (right)

On 30-JUL-04 the RICM rescue squad, assisted by Mike Rahamut of Purvis Systems, rescued a pair of PDP-11/45 systems that were part of the Brooklyn, NY fire dispatch system. They were located in an neo-Italian style public building located next to Prospect Park that was built in 1913. The building is soon to be restored so removing the equipment was important. We also rescued 5 cabinets full of electronics that interfaced to the dispatch terminals, and some of the dispatch terminal controllers.

The dispatch system used a pair of 11/45s. System-B originally included a pair of RH11 Massbus disk controllers, a RP04 96 MB disk (maybe 2), and an LP05 printer. System-B has 48KW of MF11-UP core. System-A was upgraded to 128KW of MS11-LD MOS memory. Both systems have two DJ11 (16 Serial Ports), two DV11 (16 Serial Ports with Intelligent Controller), and a DC08 (Telegraph Line Interface). Both systems boot and run RSX11-D and a special application from a single RX01 floppy disk. 

 The DV11 & DH11 serial controllers can be used with very low baud rates. The DC08 was connected to fire call boxes that were installed in buildings and on the street. When someone pulled the handle on a fire call box it released a encoding wheel that sent a unique sequence of pulses to the 11/45. The 11/45 looked up the address that corresponded to the sequence and send a dispatch message to the 911 system.