Me and the DIN plug

The DIN plug or connector is another familiar item among my collection of cables, generally in the 5-pin version, although there have been numerous others from 3-9 pins in various configurations. I think my first encounter with these was when, some time in 1971-2, my dad brought home our first cassette recorder, a Philips EL3302 (their first ever machine being the 3300 released in 1964 (see Figure 1). The mono recorder had 3 and 5 pin DIN sockets on the side, which were initially used to connect a microphone incorporating a remote switch to stop and start recording. This reflects the fact that Philips conceived of the cassette machine as a kind of Dictaphone (“Can I use your Dictaphone” “No use your finger like everyone else” – incidentally dictation was also Edison’s reason for inventing the phonograph).

Here I’d like to slot in the aside that the compact cassette (Figure 2) is an example of a class of technologies whose success is due to their specification being in the public domain – Philips having agreed to waive its patent rights under pressure from Sony and others. Other examples include the Shipping container, the World Wide Web (HTML), Android OS, and the specification for the IBM PC (see Graves-Brown 2013). Perhaps a counter argument to the more extreme models of free market capitalism?

I should say that at this time (1971-2) these connectors were not a DIN standard. My friend Rainer of the Deutsche Kommission Elektrotechnik Elektronik Informationstechnik im DIN und VDE kindly tells me that the standard for 3 and 5 pin plugs was established in 1974 as DIN 41524:1974-03, and that “At this time it needed about 15 years from starting the work till the publication was issued.” My initial surmise, was that these connectors were proprietary to Philips, later adopted as a standard (and thus also, maybe, an example of public domain technology?). The first Sony cassette machine, the TC-110 of 1971 (Figure 3) has mini jack socket connections. But in fact the first DIN plugs appear around 1959/60 and may well have been an attempt by European manufacturers to produce a cheaper equivalent to the Cannon XLR. Whatever, by the mid 70s, DIN connectors were becoming the standard, at least in Europe, for the interconnection/connection of audio devices with, in particular, the 5 pin connectors being a standard for stereo audio.

Origins

The present Deutsches Institut für Normung has its origins in 1917, when the Imperial government set up the Königlichen Fabrikationsbüro für Artillerie which soon became Normalienauschuß für den Maschinenbau and ultimately Normenausschuß der deutschen Industrie . The standards that it published were Deutschen Industrie-Normen (abbreviated to DIN). Given the date, the context is obvious, but the origin of the desire for standardisation in German industry goes back to 1907, and the figure of Herman Muthusius, who founded the Deutsche Werkbund. Together with Peter Behrens, Muthusius ideas were to influence generations of architects and designers, including Mies van der Rohe, Walter Gropius and Le Corbusier. Initially a follower of the Arts and Crafts Movement, Muthusius (a Prussian civil servant) stressed the importance of uniformity over individualism (Banham 1960) and this is what DIN came to represent, both practically and stylistically, as can be seen in the work of the Bauhaus and the “Functionalist” designs of the post World War 2 era.

The early decades of the 20^th century were the time for standards. According to the BSI  website:

“Sir John Wolfe-Barry – the man who designed London’s Tower Bridge – instigated the Council of the Institution of Civil Engineers to form a committee to consider standardizing iron and steel sections on 22 January 1901” (Note 1).

Similarly,

“In 1916, the American Institute of Electrical Engineers (now IEEE) invited the American Society of Mechanical Engineers (ASME), the American Society of Civil Engineers (ASCE), the American Institute of Mining and Metallurgical Engineers (AIME) and the American Society for Testing Materials (now ASTM International) to join in establishing an impartial national body to coordinate standards development, approve national consensus standards, and halt user confusion on acceptability.”

Initially the American Engineering Standards Committee (1919) it ultimately became the American National Standards Institute (ANSI) (see Note 2).

Making a din

All this being said, the DIN plug would now be one of the many “residual” technologies (Acland 2007) if it hadn’t found some other uses (and its final demise may not be far off). Firstly, DIN connectors were commonly used on computers, such as the Acorn BBC B, and the aforementioned IBM PC, where keyboards were (initially) connected using a 5pin DIN (Figure 4). IBM‘s team, headed by Don Estridge, chose to use off the shelf components for the PC of which, presumably, the DIN plug was one, and which ultimately helps to explain the success of the PC format – off the shelf parts and an open source BIOS rapidly led other companies to clone the PC. Ultimately the DIN connector was replaced on IBM‘s third generation PC; the PS/2 whose mouse and keyboard connectors are still in use today (albeit rapidly being replaced by USB). I will have more to add on this in my projected posting on the Molex connector.

Meanwhile, Dave Smith of Californian synthesiser manufacturer Sequential Circuits had used the 5pin DIN as a basic component for a universal synthesiser interface which, after much negotiation between manufacturers, was launched as the Musical Instrument Digital Interface (MIDI) in 1982. This remains very much in use to this day, probably the last major field in which DIN plugs are deployed, albeit that here too DIN is being superseded by USB on synthesisers, keyboards and other controllers. It should be noted that Smith probably chose the DIN plug because it had already been used on a number of Roland‘s devices which went on sale in 1981, particularly the CSQ 600 sequencers, the legendary TR808 (drum machine) and TB303 (synthesiser) – which I owned at one time (apart from the TB303 see Figures 5 and 6). In Roland‘s case the DIN plugs carried their proprietary sync 24 signals that were a kind of prototype MIDI. Also I should note that the MIDI interface, unlike many other connectors, used an internal optical connection; the idea being that even when connected together, devices were electrically isolated from each other to avoid one faulty device damaging another.

How long will the DIN plug survive and what explains its imminent demise? The name Universal Serial Bus gives us a clue – it is becoming relatively universal and although maybe not technically as good as Firewire, it transfers data very rapidly. By comparison the DIN based MIDI interface system is notoriously slow. Simply obsolescence? Yet the jack plug survives, as does the RCA phono still found on most Hi-Fi equipment where once there were 5 pin DINs. DIN plugs and sockets are also relatively large, which is presumably why IBM switched to the smaller PS/2 connector. Here there is, perhaps, a parallel with the jack plug, whose smaller 3.5mm variant is now predominant. When it comes to connectors, size does matter, it seems.

Notes

Note 1: This statement is not entirely correct; the basic design of Tower Bridge was the work of Horace Jones, the City of London’s architect. My understanding is that Wolfe-Barry (the son of the architect of th Palace of Westminster) did the neo-gothic cladding on Jones steel structure.

Note 2: These are by no means the first efforts at standardisation, for example, in the 19th century Joseph Whitworth created standards for screw threads that are still in use today, see Machine Tool. Not forgetting the metric system.

Note 3: Though maybe not the “street finding uses for things” its interesting that the design of the EL3302 as a dictation machine made it ideal as a data cassette for early home computers, in that its remote functions allowed the computer to control the tape when uploading or dumping data.

Sources

Acland, Charles R 2007 Residual Media: Residual Technologies and Culture. University of Minnesota Press

Banham, Reyner 1960 Theory and Design in the First Machine Age. London: The Architectural Press.

Graves-Brown, Paul 2013 The box and the Encinal Terminal: an archaeology of globalization. Post-Medieval Archaeology 47/1, 253–260