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

Rob Doyle doyle at cox.net
Sun Jan 30 16:20:52 CST 2022

On 1/30/2022 2:56 PM, Glen Slick via cctalk wrote:
> 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.
> http://www.bitsavers.org/pdf/dec/unibus/MP01118_KMC11B_EngrDrws.pdf
> 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

If anybody has any schematics for the KMC11 (not the B version), I'd
love to get a copy of them.

The KMC11 and the KMC11-B are relatively incompatible with each other.
The KMC11-B has 4x more data memory, has 4x more microcode memory, and
loads microcode in a completely different way.

I have a KMC11 implementation in my KS10 FPGA, but it's implementation
is based on guesses and reverse engineering the diagnostics.

Thanks in advance.

Rob Doyle.

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