The Telematico NMS3000 - Celso Martinho

The Telematico NMS3000

Posted on Jun 13, 2026

It’s been a while. This time, I’m continuing the “computers that I never had” series to talk about a project that has been sitting on my bench for literally months, waiting for a little less busy times to complete: the Philips Telematico NMS3000.

The Philips Telematico NMS3000

There are a couple of reasons why I bought this relic to work on: it takes me right back to the pre-Internet days of modems, X.25, and Videotex; it’s simple enough that I actually stand a chance of fully understanding how it works; and it has near-zero information available on the Internet. That last part forces me to discover things on my own, which, if you’re the rabbit hole type, you know is the best part.

What is Videotex

For the uninitiated, Videotex followed the Teletext standard found on TVs in the early 70s and was an early, pre-Internet, two-way electronic communication system enabling users to communicate and interact with information services via standard telephone lines and a terminal with a modem, displaying text and rudimentary graphics on a screen. Videotex, like Gopher was a precursor of the Internet.

A lot of European countries had their own thriving Videotex services. France had the famous Minitel, and here in Portugal, we had a service provided by the now decease Telepac. We could access Videotex via a standard dial-up line or an X.25 packet-switched connection, provided we had the necessary NUA (Network User Address) credentials. The coolest part about our local service was that it provided a bridge to international services—meaning we could jump to the French Minitel network.

A Portuguese bank announcing their Videotex service (video)

The Loewe VTXTEL-CP terminal used in Portugal

I vividly remember (ab)using my university’s X.25 connection in the pre-Internet days to access Minitel, specifically to get onto QSD, a somewhat popular hacker chatroom service. But those are stories for another day.

QSD Chat

In a way I see Videotext and Gopher as the precursor systems of the Internet.

And yes, it’s Videotex , not Videotext.

What is the Telematico

The Telematico is a dedicated Videotex terminal launched in 1988, specifically tailored for the Italian market to access their Videotel service.

Under the hood, this terminal features:

A Z80 CPU clocked at a “blazing” 3MHz

32K of ROM and 4K of RAM

A 256-byte EEPROM to save user configurations

A CEPT Videotex Level 1 video decoder

A built-in CCITT V.21 and V.23 (1200/75 baud) capable modem

Telematico PCB

Architecture-wise, the Telematico is loosely based on the MSX1 standard—a platform Philips knew inside and out because they manufactured plenty of MSX computers themselves. But it’s not really a MSX. The ICs on the board are standard fare for late-80s hardware, with one massive exception: a mysterious, proprietary 40-pin chip labeled “Celint” that handles Videotex decoding and video generation. More on that in a bit.

Alright, let’s turn this thing on.

How do I even power this up?

Like I mentioned, documentation for this terminal is virtually nonexistent online. I couldn’t find a user manual, let alone schematics, and the unit arrived bare-bones—no cables, no power supply. Luckily, I stumbled onto a single webpage that included this connector diagram:

Video and Power connectors

Well, it’s a start. These are standard 8-pin and 4-pin DIN connectors, which means I can actually build my own cables.

For power, I decided to use a DC-DC PicoPSU-150-XT ATX power supply mated to a screw-terminal adapter. Standard ATX power supplies don’t output a 10V line, so I put two diodes in series to drop the 12V rail down to roughly 10.6V, which hopefully is within tolerance for the terminal.

PicoPSU power supply for 5V, -5V and 12V converted to 10V

As for video, the Telematico outputs RGB + sync. This works beautifully with my Retro Scaler 2x to upscale and convert the analog signal to clean HDMI for modern monitors.

Retro Scaler 2x connected to the Telematico

One last hurdle before flip-the-switch time: the way that the keyboard is connected to the mainboard leaves almost zero maneuvering space if you want to probe components while the machine is running. To fix this, I hacked together a quick extension harness using a mess of jumper wires and blue tape.

Retro Scaler 2x connected to the Telematico

I think we’re ready now.

Retro Scaler 2x connected to the Telematico

I flipped the switch. The classic Philips logo materialized on the screen, followed immediately by the dialup phonebook and configuration menus in Italian. Success.

Bringing the Telematico online

The next logical step is connecting the terminal to another computer. This sounds simple on paper, but it obviously never is. There is no serial port, no parallel port, and no expansion bus. The only way data leaves this machine is through its modem and a telephone line.

So,...