DTE20 Ten-Eleven Interface

The DTE20 Ten-Eleven Interface (also called the DTE20 Console Processor Interface) is a peripheral on KL10 CPUs which allows a PDP-11 to act as a front end. Depending on how the DTE20 is configured ('restricted' or 'privileged') , it can be just for off-loading I/O functionality to the PDP-11 (both to reduce the load on the main CPU, but also to allow access to the wide range of peripherals supported on the PDP-11), or it can also function as a control and diagnostic system for the main CPU: loading microcode, bootstrapping, etc.

The PDP-11 and KL10 are able to examine each other's main memory (limited on the KL10 side for restricted DTE20's), and interrupt each other.

A KL10 may have up to 4 DTE20's, and a PDP-11 may host up to 4 DTE20's on different kL10's.

Implementation

The DTE20 is connected to the EBox of the KL10 via the EBus; privileged DTE20's also have access to the KL10's diagnostic bus. To the PDP-11, it appears as a normal UNIBUS peripheral.

It consists of a number of hex boards plugged into an I/O backplane of the KL10; these are connected to a UNIBUS connector mounted lower down in that rack, and a BC11A cable from the PDP-11 (usually a PDP-11/40) plugs into that.

External links

• DTE20 Ten-Eleven Interface Unit Description
• KL10-Based Physical Description - contains images of DTE20 backplanes and wiring, pp. 3-7-3-11; board configuration, pp. 3-27,3-28