Transdata's Cx 500 microcomputer family: the problem solvers

Here's another Z80-based system, albeit with a slight twist in that it's aimed not just at business but at the scientific community.

The entry-level Cx 502 had a [!Z80|Z80A] CPU, 64K RAM and twin 8" IBM-format floppy disk drives, whilst the top-of-the-line Cx 504 swapped one 8" disk for a 20MB Winchester hard disk, as well as coming with a tape backup unit.

Slightly unusually, the Cx 500 range shipped with four V.24 serial interfaces - a standard more commonly associated with modems. 

Armed with the company's "Comspak" communications software package, it was possible to connect directly to "most remote computers".

[picture: JohnNeale_microandmicro_may82.webp|Transdata's directors, featuring head of production Roger Neale, founder and managing director John Neale, and head of marketing Ivor Smith. From Microprocessors and Microsystems, Vol 6 No. 4, May 1982]

Transdata had been founded in 1970 by John Neale - along with twin brother Roger and Ivor Smith - thanks to Phoenix Insurance needing a way of transferring a huge database from the company's old LEO III/33 to a new IBM 360[source: https://www.leo-computers.org.uk/images/04_LEOPEDIA_OBIT_XXX1021.pdf].

Neale, being familiar with both systems, offered to automate the process and used the contract as a basis to start his company - appropriately named Transdata - based in Havant, near Southampton.

By the early 1970s it had produced a thermal printer range - the 300 Series - which was followed by a floppy disc interface for DEC's PDP-11 and a microprocessor-based floppy disc controller, using Intel's 8008.

Transdata's thermal printer technology also appeared to make its way into one of the first portable "computers" - a terminal with a built-in "silent" thermal printer as its output - with its Model 305, otherwise known as the Executive Terminal, which was first launched in 1972.

Although it was aimed at the aspirational "James Bond" executive, that wasn't where Transdata ended up selling, with managing director Neale pointing out alternative uses including an early example of remote working:

~"With hindsight, it was not company executives who were interested in portable computing, they had little knowledge or experience of computing. It was the protective enclave of the data processing department. An interesting customer for these terminals, because they required no PTT modem and could be outlocated as demand required, were the programmers at ICL on maternity leave, since they could be easily located in employees homes economically. All other sales came from the Computer Time Sharing companies[source: "The laptop : design or desire?", Paul Atkinson, Sheffield Hallam University, 2001, p. 3 https://shura.shu.ac.uk/8673/1/Laptop_Aveiro_2.pdf]".

Transdata's terminal, as well as others such as Texas Instruments' Silent 700 - as used in the [=micronet800_elecompmnth_nov83|Lamberti and Filinski hack] of 1987 - remained the only form of portable computing for the next five years. They also were considered by some to have been the first stepping stones on the way to the true laptop[source: "Man in a briefcase: the social construction of the laptop computer and the emergence of a type form", Paul Atkinson, Sheffield Hallam University, 2005, p. 5 https://shura.shu.ac.uk/965/1/fulltext.pdf]. 


[picture: Transdata_hq_microandmicro_may82.webp|Transdata's head office in Havant, near Southampton. From Microprocessors and Microsystems, May 1982]

With what was essentially a general-purpose processor board in its floppy controller, Transdata realised it had all the components to build its own microcomputer, which it did when it released its Cx 400 series in 1977. 

As there was something of a lack of operating systems and languages at the time, it ended up developing its own Transdata BASIC to run on the machines.

By early 1980s, the company - which by now had three offices in the south-east of the UK - wanted a machine capable of running CP/M, and so its switched from the Intel 8080 to Zilog's Z80 and created the Cx 500 Series, launched in 1981. 

[picture: Transdata_cx502S_prac_feb82.webp|An advert for the Transdata Cx 502-S Superspeed, launched at the Which? Computer Show. From PRAC, February 1982]

The company was back the following year with the Cx 502-S, which was launched at the Which? Computer Show in 1982[source: https://t-lcarchive.org/transdata-101-dd/].

The new model was now running a Zilog Z80B at 6MHz, giving it a 50% increase in performance. 

It also had another Z80 in use as an "intelligent" floppy disc controller, which apparently helped give it a performance five times better than conventional floppy-based CP/M systems.

At the launch, it retailed for £3,500, which is about [[3500|1982]] in [[now]]. At the time, the company had a turnover of around £2.5 million and employed 110 people, of which around 15 were in R&D with another 37 in sales and service.

Head of marketing, Ivor Smith, attributed the company's survival to having found a niche "where the power of the giants is less".