UNICHANNEL 15 System

The UNICHANNEL 15 System (UC15) is an group of hardware sub-systems which allows a PDP-15 to communicate with a PDP-11 (usually a PDP-11/05) which acts as an I/O front end, partially to offload the PDP-15's CPU, but also to allow PDP-15 systems access to devices which did not have native PDP-15 support, such as the RK05 disk drive. The UC15 includes two separate sub-systems:

• An MX15-B Memory Multiplexor, which allows the PDP-11 (both the CPU, and DMA devices on the PDP-11's UNIBUS) access to the PDP-15's main memory.

• A data channel between the two CPUs, which allows them to interrupt each other; this channel is implemented with a pair of DR11-C general device interface parallel ports, and a DR15 Device Interface.