Archive for the ‘Exelvision’ Category


March 10, 2021

As I said in another blog post I find the computers of the 1980s French company Exelvision interesting and under-appreciated. Not only featured these computers (French) speech synthesis, but it had also one of the most interesting and quirky add-ons of the 80s: a digital drum computer (well, sort of)! Fitting into the naming scheme of Exelvisions products, it was called the “Exeldrums”. It was first sold in 1985 for 1200 French Francs (about 400 USD today).

Exeldrums: Complete product (without the manual)

Exelvision’s computer already came with a TI TMS5220 speech synthesis chip that was the same as in some of TI’s other products like the (last version of the) speech synthesis module for the TI-99/4A, the BBC Micro, and several arcade machines. It used something called “pitch-excited linear predictive coding (PE-LPC), where words are created by a lattice filter, selectably fed by either an excitation ROM (containing a glottal pulse waveform) or an LFSR (linear feedback shift register) noise generator. Linear predictive coding achieves a vast reduction in data volume needed to recreate intelligible speech data.” [Wikipedia]. The thing is that the Exelvision computers did not have a regular sound chip. In principle, you could use the speech synthesis chip also for sound effects, but it was a very complicated process to calculate the data for the synthesis chip given a target audio file. What Exelvision offered was to send them an audio cassette with the audio, then they would send this cassette to some TI labs in Dallas where a VAX computer would calculate the necessary data to feed the chip which you would get back as data on the cassette. As a result, even Exelvision’s own games have very sparse sound effects (and a lot of speech).

You could use a trick to generate some single channel audio, though. This trick consisted in using the cassette interface(!) and the timer to generate tones of a certain pitch and duration (see the last example in the section “Le composant audio” in [2] for an example).

So, all in all, the Exelvisions were not the best computers to do audio. Therefore, maybe in order to increase the attractivity of the machine to this market segment, two of the Exelvision engineers developed a cunning plan to use the computer as a drum machine (or at least a rhythm device). In true Exelvision fashion, an extension module was designed (all Exelvisions have an extension bay in the back), and some software written and put in a cartridge (they also had a cartridge slot in the front).

The module was designed around a rythm chip from Hohner (yes, the 150+ year-old German musical instruments manufacturer famed for their harmonicas). You see, Hohner used to manufacture a lot of different instruments in their day, and were in the 1960s and 1990 also famed for their range of innovative and popular electromechanical keyboard instruments. Between 1968 and 1976 they even produced (small) computers. In 1982 Hohner brought a successful series of home organs to market. Some of these models were sold in the US under the Wurlitzer brand, but stating on the case „Computer System by Hohner“.

This rhythm chip (the PCF0705) was manufactured by Philips. It is an interesting, but quite obscure chip. We know, of course, what it can do (see below), but apart from that we know basically nothing about it, not even a data sheet is available. This is because most probably, this chip was used only in Hohner products, and in Exeldrums…
All I found was a mention of this chip in a (Hohner designed) Wurlitzer “WX42 Keyboard Computer” because the seller mentions that you need to replace this chip if you want to get rid of the noise in the rhythm part of the keyboard…

Now, what can the Exeldrums do? Well, you can play 6 instruments in parallel out of a library of 17 drum and percussion sounds. These 17 instruments are clustered in 6 channels, and you can select one instrument per channel per time. The toms and the maracas are duplicated on two channels, so you can add them more often:

  • channel 0: bass drum, tom 1, tom 2
  • channel 1: hi-hat open, hi-hat closed
  • channel 2: cymbal, maracas
  • channel 3: snare drum, roll, brush, rim-shot
  • channel 4: maracas, tambourine, claves, tom 1, tom 2
  • channel 5: bell, hand clap

The resulting sound is probably good enough as a rhythm for a home organ, but it is no TR707: all sounds have the same length and the same volume.

The hardware module consists of the Hohner chip, a 32 kB ROM, a tiny (128 bytes) static RAM chip, and an analog/digital converter. You can hear the sound either via the TV or via the stereo cinch output at the back of the module.

Exelvision is a French company, producing computers mainly for France, and also the manual for the Exeldrums is in French. The software, however, has an English user interface 🙂

The basic screen is the classis TR707-style measure x sounds grid and you mark the beat where a sound shall be played. You can change the BPM, and you can have up to 57 sequences that can be saved onto tape or ExelMemory. In the software, you can use also one of 16 predefined rythms. Exeldrums can also be played from the Basic.

Here are all instruments (bass drum, tom 1, tom 2, hi-hat open, hi-hat closed, cymbal, maracas, snare, roll, brush, rim shot, tambourine, claves, bell, hand clap) played one after another each for 8 beats:

All instruments for 8 beats each, 50 bpm

There you have it: The Exeldrums digital “drum computer” module for the Exelvision family of computer in 1985. A rare and quirky add-on for a relatively rare French computer.


Exelbasic + (Plus)

September 2, 2018

exelbasicplusSome time ago, I acquired an Exeltel VX. Like any other flavour of Exelvisions computers (the EXL100 and the other Exeltels) it has no built-in programming language (in case of the Exeltel VXs this would have been a lesser problem anyway as it wants to be a Videotex terminal). However, if you want to load anything from a cassette (or a floppy disk or a battery-buffered RAM) you need your Basic. Exelvision delivered one with every EXL100, the Exelbasic.

In order not to have to borrow an Exelbasic from a friend (hi, cobrakai!), I bought one from Ebay (which does not appear that often as one wants, especially for a sane price). What I ended up with was not an ordinary Exelbasic, but the improved Exelbasic + (Plus) which I did not even know existed. Instead of a measly 200 pages of (French) manual, you have a 300 page one (also French). I am happy!


Exeltel and Exelrecorder

May 10, 2018

A pro tip for people trying to connect an Exelvision or Amper Exeltel to a Exelrecorder: use a 8-prong DIN cable (270 degrees). If you don’t, you might wonder why the damn thing isn’t saving or loading :-). Okok, I’ll explain. The Exeltel is an interesting (by and large unsuccesful) 8-bit computer that incorporates a modem (and therefore, a telefone connection) for different purposes. One of these purposes was the use as an answering machine. Due to the lack of compute power and digital storage capabilities (8 bit, we remember) this means that you want to record to a cassette tape (using analogue audio, of course). In order to do that the computer has to be able to remote control the cassette recorder. In order to do that you need: a) a cassette recorder that can be remotely controlled, and b) a cable that provides the additional lines to control the recorder. That’s why there is an accessory for the Exeltel: the Exelrecorder.

There was also a quite standard cassette recorder (called the K7) for the predecessor of the Exeltel, the EXL100. This recorder and the EXL100 use a standard 5-prong audio DIN cable because there was no remote control need for that machine. The Exeltel and the Exelrecorder, though, need an 8-prong DIN cable for the additional functionality. Now, my problem was that I had an Exeltel and an Exelrecorder, but no cable. I tried it with a 5-prong cable, but the Exelrecorder would not start recording or playing. Only when I bought the 8-prong version, everything worked. If you have the same problem you’ll find that 5-prong DIN cables are hard to come by today, but an 8-prong one reduces your choice of shops to a very small number.

Amper Exeltel VX

January 1, 2018

Exelvisions EXL 100 and Exeltel are some of the most interesting under-appreciated home computers of the 80s. This under-appreciation stems partially from the fact that they were available basically in only one country (France) and that they had stronger competition (Thomson) in this market. And, of course, that also had all the ingredients of computer models that often appear in this blog: from a consumer point of view they were neither price-wise nor feature-wise appealing.

The story starts with former employees of Texas Instruments France who take a lot of the technologies developed there for the TI CC-40 and build a home computer around it: the EXL 100 from 1984. The features that owe to this heritage are:

  • the CPU (a TMS 7020)
    As far as I can tell this is and the CC-40 (which uses a CMOS version) are the only computers with this CPU.
  • the speech synthesizer and sound chip
  • the infrared connection between keyboard, game controllers, and main unit
  • the graphics chip
  • the Basic (although in an improved form)

The system is highly modular, with detached keyboard and game controllers, the Basic is on a cartridge. Therefore, the ROM is with 4 kB very small.

The next (and last) model of the family is the Exeltel from 1986. As the name indicates, this model is all about communication (i.e. the communication that was broadly available around this time frame: telephone-line-based things). The main difference to the EXL 100 is the now integrated V.23 modem using, of course, a TI chip (1200/75 bps, it was an accessory for the EXL 100). Smaller differences are the upgraded CPU (now a TMS 7040 (this is the only computer with this CPU)), the possibility to connect a (better) keyboard, more RAM, and much more ROM (82 kB). The ROM still does not include the Basic, but a program that allows to exchange files between Exeltels via the modem, an answering machine feature (in some versions, uses an attached cassette recorder), a speech synthesizer program, some educational programming language, and some windowing support. Exeltels also come with 16 kB RAM module bundled with them.

From now on, newer models differ only in ROM content, not in hardware.

The Exeltel VS renders the Exeltel into a Prestel terminal supporting the French Prestel standard, Minitel. For our younger audience I have to explain what Prestel, Minitel, BTX, etc. actually is. You see, kids, before the Internet took off widely, in Europe people thought it would be a good idea to have some sort of cloud network on some central computers that ordinary people can use by small computers and telephone modems, possibly connected to TVs. The computers would be so small (and cheap) that they were not expected to execute programs, but to display pages with text and pseudo graphics as well as forms that could then be send back to the cloud. Using this simple system, users could use electronic telephone books, send messages to each other or do Electronic Banking. For a limited amount of time (say, 1983 to 1993) this was very popular, also because it was by and large the only alternative and because it was offered by the national telephone companies. The first of these systems was Prestel in the UK. Later on, Minitel in France, and BTX in Germany offered similar systems. The systems were roughly the same, but were not standardized completely (although some partial standards were used).

The Exeltel VS is said to have bundled also a connector module that offers a serial and a parallel interfaces as well as a mouse interface.

The next model is the Exeltel VX, which is an Exeltel VS, but with multi-norm Prestel support, namely for:

  • CEPT 1 systems like BTX (Germany, Austria) and VTX (Switzerland)
  • CEPT 2 systems like Minitel (France)
  • CEPT 3 systems like Prestel (UK, Australia)
  • Ibertex (Spain)
  • Mistel (Belgium)

Now, you might think, ok, so this is your model, right? Are we done? Well, the answer is: not yet. You see, I got an *Amper” Exeltel VX. So, what’s the difference?

Well, Exelvision wanted to expand into other European markets, in this case the Spanish market. Therefore, they partnered with the Spanish telecommunication manufacturer Amper, owned by the national Spanish telco, Telefonica. The firmware is translated into Spanish, even the speech synthesizer is fitted with a new software version that can output Spanish sentences. Also software is translated into Spanish (in the end about 50% of all titles are also available in Spanish). The Amper Exeltel is sold exclusively via the Spanish “El Cortes Ingles” chain of shops. Apart from giving its name Amper is not involved too much in the lifecycle of the devices, however, they do Quality Assurance for the Spanish models and also After Sales Service.

The Spanish market in the 80s has a funny peculiarity: If you import a computer into Spain with 64 kB RAM or less, you have to pay some hefty additional fee (like 90 Euros). Therefore, there exist models like the Amstrad CPC 472 which has an additional 8 kB RAM soldered on the PCB that is non-functional. Exelvision solves this problem (as it has nominally only 2 kB RAM) by bundling a battery-buffered 64 kB RAMdisk module with the Amper Exeltel.

As in Spain, Prestel is not widely used for a long time (until this changes in 1992), the Amper Exeltel is not a success. Especially as Exelvision closes down for good in 1991.

Technical Data

Manufacturer: Amper
Model: Exeltel VX
Introduced in: 1986
CPU: TMS 7040@4.9 MHz
RAM: 66 kB + 64 kB Ramdisk
ROM: 38 kB
Text Mode: 24 x 40
Resolution: 320 x 200, 8 colors
Interfaces: cartridge slot, exelmémoire slot, expansion slot, tape-recorder, keyboard, IR, power, telephone line, RGB video output

The premier resource (in French). Most of the information in this entry were taken (and translated) from that site.