What was a Terminal Concentration Device in DEC's products?

Glen Slick glen.slick at gmail.com
Sun Jan 30 15:56:32 CST 2022

On Sun, Jan 30, 2022 at 11:43 AM Chris Zach via cctalk
<cctalk at classiccmp.org> wrote:
>  From the books, the kmc11 had an "lsi11 on board", 1k of 16 bit ram, 1k
> of 8 bit data memory a 300ns cycle time, 16 bit microprossor with a 16
> bit micro-instruction bus and 8 bit data path. This is according to the
> 1980 Terminal and Communications handbook, so it's a few years after the
> 1976 timeframe of Sha Tin.
> Now the original LSI11 processor was 4 main chips, an EIS/FIS chip (or
> the CIS lite chip or the weird 1k*20 bit micro-ram board which I have
> somewhere). The DCT11 was a single chip lsi11 that had an 8 or 16 bit
> outside bus and a 16 bit internal structure and ran pdp11 instructions.
> So the KMC11 probably had the DCT11 chip.
> The LSI11 chipset was around in 1975, so it makes sense that DEC could
> use it. The SBC11/21 came out in 1981 but the chip was probably avail
> internally by 1980 so I'm guessing that the KMC11 and the COMM-IO-DP was
> using the DCT11.

KMC11-B Field Maintenance Print Set

The KMC11-B used a custom bit-slice processor implementation.
(3x) 93S16 4-bit counters for a 12-bit program counter
(2x) 74S181 4-bit ALUs for an 8-bit ALU
(2x) 74S189 16x4 RAM for 16 8-bit working registers

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