Integrated computer systems Inc. Computers

Portable Microprocessor Training Lab (8080)

Overview

The Portable Microprocessor Training Lab is an 8080 based computer from Integrated computer systems Inc. (ICS) that was intended for self-study, and appears to be from around 1978. As of 2025 there is currently little information online about its availability although the documentation archived online (see Resources section further down the page) provides lots of technical information. The lab consists of the Microcomputer Training System (MTS), and expansions Interface Training System (ITS) and Integrated Experiment Assembly (it seems ICS didn't use an abbreviation for this part but often called it 'Experiment Board' in the documentation), as well as the power supply. However, the MTS was the minimum that needed to be purchased to have a working but unexpanded computer, along with the power supply as an optional extra or the user could use their own suitable power source.

As the heart of the system, the MTS is made up of the PCB containing the 8080 8-bit CPU, 2KB RAM (upgradable to 4KB), 1KB Monitor ROM (with support for three additional ROMs), control logic, 25 key keyboard (16 white 'hex' keys and 9 coloured function keys), alphanumeric display along with the protective transparent cover. For expansion, and forming part of the Portable Microprocessor Training Lab, the ITS interfaces with the MTS via a keyed ribbon cable, the ITS provides I/O ports, ADC, timers, and a vectored priority interrupt control system. For further expansion the Integrated Experiment Assembly PCB plugs into the ITS PCB and is furnished with a loudspeaker, thermistor, motor (a battery holder for 3 AAs powers the motor), opto sensor, switches and pots (variable resistors). Lastly, the power supply delivers -5V, -12V, +5V, and +12V to the MTS PCB and the additional boards.

It would appear that the computer originated in the US since Integrated computer systems Inc. was based there and in 2025 when I came across the computer they were being sold on eBay from the US, for around $500 to $900 (~£370 to ~£666). Since I have what appears to be the UK or European version it was likely also sold in Europe (I bought the computer from a UK eBay seller), there is a German video on YouTube showing the computer so that further suggests availability in Europe. Here is the video:

Notice that they have the MTS and power supply (supporting the MTS underneath) only, so it's the unexpanded version.

You can view a video I did about the Training Lab:

As mentioned, the MTS uses an 8080 8-bit microprocessor originally released in 1974 by Intel, a processor which helped sparked the computer revolution. The actual version used in the MTS may be from any manufacturer, for example my computer uses a P8080A which is from AMD as it has an AMD copyright date (1977) on the chip along with the AMD logo. AMD initially made unauthorised clones of the Intel 8080 for sale in 1975 using the part number 9080A, but from 1976 AMD became an official second source for Intel. The actual date on the 8080 in my lab appears to be '84 as it has written on the chip 8426DMA, other chips on the MTS PCB are from the same year.

The 8080 in the MTS runs at 2.048MHz, which is achieved through an 18.432MHz crystal fed to an 8224 clock generator/driver chip, dividing the crystal frequency by 9.

In addition to the main 'Monitor' ROM, which lets you enter and run programs, the MTS also supports three additional ROMs, which for the courses that accompanied the computer contained demo programs that made use of the features supplied by the ITS and Experiment Board. The available ROMs were Thermistor Program (THCL) ROM, Tune and Message Program (TUNE) ROM, and Motor Speed Program (MTRSPD) ROM. Of course there is no reason why you can't program and install your own ROM instead of one of the demo ROMs and make use of the code routines in the Monitor ROM.

The main form of feedback to the user provided by the MTS are the eight 7-segment red LED displays which of course can display hexadecimal, however, ICS made an odd choice to avoid ambiguity issues. Firstly, there is the problem that 'B' could be mistaken for '8' so ICS decided to represent 'B' by lighting segments a, c, d, e, and g but what they could have done was use a lowercase 'b' (segments c, d, e, and g) and for '6' do the same but with segment a also lit. ICS did sensibly decide to show 'D' as a lowercase 'd', however. In addition to showing hex characters, 'R' can also be displayed which is shown essentially as a lowercase 'r' - segments e and g lit.

I've illustrated in the following image to make it clear how, from left to right, 'B', 'D', and 'R' are displayed by the MTS:

As mentioned the Integrated Experiment Assembly provides further expansion and is used by some of the demo programs contained in the ROMs. As well as the previously mentioned components, the PCB also has four switches labelled SPKR, EXT.4, MOTOR CONTROL, MOTOR POWER, as well as VOLUME and THERM. ADJ.  which are speaker and thermistor adjustment controls respectively.

The Portable Microprocessor Training Lab I bought was £241.95 ($324.67) shipped, the listing specified 'untested sold as seen', unfortunately I got no documentation with the lab but as mentioned a lot of documentation has been uploaded online and can be found in the Resources section. The case (see below) has obvious scratches and rusting on the metal (which I had seen from the seller’s photos), that can possibly be dealt with. To me the case is a very handy bonus but it's the PCBs that I was most concerned about, fortunately the PCBs are in very good condition with no signs of leaking around the battery holders on the Experiment Board. Even though the computer came in the case the seller still packed it well in the shipping box, which was must appreciated.

Notice on the side of the case with the handle and latches there is a label that says 'INTEGRATED COMPUTER SYSTEMS, INC. MICROCOMPUTER TRAINING SYSTEM', which is interesting as the MTS is only a part of the lab although it is the main and most important piece.

Next up is a photo showing a large label which reads:

THE PORTABLE MICROPROCESSOR TRAINING LAB

INTEGRATED COMPUTER SYSTEMS

EDUCATION IS OUR BUSINESS

It also lists a USA Office address in California and European Office in England - the fact that there was an office located in England strongly suggests that the computer was indeed sold in the UK.

As can be seen in the following image, on the bottom of the case near the hinge is a (wonky) label (upside down), which says:

MICROPROCESSOR TRAINING LAB

6548

INTEGRATED COMPUTER SYSTEMS, INC.

The number is possibly a serial but may also give an indication of the minimum number that were made in the UK at least.

The bottom of the case has four 'feet' so the hinge doesn't scrape whatever it's put on.

Here is a side view of the case where you can see the power supply (the triangular metal piece) supporting the MTS:

Also visible is the (black) mains cable and the (grey) audio cables.

Here is a view of the top of the MTS where you can see the power connector top left, the S-100 connector to the rights of it, and the ITS connector further right:

Also of interest is the 8080 under the power connector, which is an AMD version of the 8080. The plastic covering over the MTS PCB has written in white 'INTEGRATED COMPUTER SYSTEMS, INC. MICROCOMPUTER TRAINING SYSTEM'.

Here is a close up of the left side of the MTS:

Notice how the power supply connector doesn't use all the pins of the MTS J1 connector.

Next is a close view of the top right part of the MTS:

You can see the S-100 connector to the left and the ITS connector to the right of it, as well as the OUT and IN phono connectors, and the AUDIO and DATA LEDS. On the right side is the TP connector, which appears to be a series of test points - on the AMTS schematic (see the bitsavers link in Resources section) there are various test points marked (TP1, TP2, etc.) that match the labels on the MTS PCB although there are some (e.g. TP12) on the schematic that aren't labelled on the PCB.

Also visible toward the top right of the photo is the UK plug which is part of the mains cable which of course is plugged into the power supply.

The Integrated Experiment Assembly a.k.a. Experiment Board (left) and the ITS (right) can be see in the next photo:

On the ITS it is called 'MICROCOMPUTER INTERFACING SYSTEM'. The ribbon cable connecting the ITS to the MTS can be seen to the right of the ITS.

And a close up of the Experiment Board is next:

Note that on the PCB it is called the 'EXPERIMENTAL PARTS ASSEMBLY'.

Of the few chips I've checked so far on the MTS PCB they have a date of ‘84, suggesting that the computer was sold for at least 6 years if it was indeed originally released in ‘78 but you also have to consider that it may not have made its way to the UK until the '80s. The power supply, located under and supporting the MTS PCB is rated for 230V and has a UK mains lead plugged in so indeed my version is a UK or at least EU version of the lab.

A nice touch is that the different parts of the MTS PCB are labelled as the computer was educational, teaching the basics of computing.

There are four RAM chips installed, each MN2114-4, which are 450.0 ns 1K x 4 SRAM, with four empty RAM sockets. This equates to 2KB but installing four more RAM chips would give 4KB total.  Since the CPU is 8-bit you'd need to install RAM in pairs. Images online of the computer also show four RAM chips installed so 2KB RAM seems to have been the standard.

Although the plastic cover above the MTS PCB helps protect the components, a few of them are bent over. I did notice a few tantalum capacitors so they’ll need checking as they often fail and the power supply will also need servicing and testing independently of the PCBs before powering the boards.

Technical

Memory map

Address (hex) Description

0000 - 03FF AMTS MON Monitor ROM.

0400 - 07FF ROM Position 1. Usually occupied by THCL Thermistor Program ROM.

0800 - 0BFF ROM Position 2. Usually occupied by TUNE Tune and Message Program ROM.

0C00 - 0FFF ROM Position 3. Usually occupied by MTRSPD Motor Speed Program ROM.

1000 - 7FFF Undefined.

8000 - 83FF RAM Pair 0.

8400 - 87FF RAM Pair 1.

8800 - 8BFF Empty RAM Pair 2.

8C00 - 8FFF Empty RAM Pair 3.

9000 - FFFF Undefined.

Notes:

AMTS=Advanced Microcomputer Training System.

The Monitor ROM must be located at hex addresses 0000 - 03FF, and it relies on having RAM at hex addresses 8000 - 83FF.

Resources

Various documentation:

https://bitsavers.org/pdf/integratedComputerSystems/

https://vtda.org/docs/computing/ICS/

All content of this and related pages is copyright (c) James S. 2025