Product: Merlin M2105
Publisher: British Telecom
Compatibility: Acorn Electron
Reviewed by: Bill Perry
Originally published in EUG #67

Two years ago, we pieced together several snippets of information from different sources to review the BT Merlin M2105 Comms Terminal. We also appealled for any more information about this scarely known Acorn Electron variant and finally, in October 2006, ex-British-Telecom-engineer Bill Perry obliged us with a full history of the Merlin system. Whereas the first article mainly concentrated on the computer itself, Bill has now furnished us with much more of the background. Whilst both articles devoted to this system may seem a bit dry to those whose interest in the Electron extends no further than games and demos, we feel sure there will be a smattering of hardcore Elk fans just dying to know what that mystery machine was... so peel pack your ears whilst we divulge its secrets.

In 1984, when real keyboards were replacing rubber ones, when computers had evolved to a stage where bedroom coding was becoming a national pastime, and when the machines themselves were manufactured with enough kilobytes to be programmed with extremely complex (for the time) procedures, British Telecom was, quite naturally, wondering how this technology could be harnessed to help business. The M2150 was just one in a long series of models of machine, which it manufactured an expansion for, attached, and then renamed to sell as a complete model. The Electron was but one example of this - BT also bought up stocks of Logica's Kennet computer, ICL PC's running CPMs and wordprocessors, Zenith PCs and countless others. The expanded machines were shipped out to companies in their thousands, finding work in everything from the DSS to the Navy.

All of this engineering took place in approximately eight bases around the United Kingdom, where, presumably, men in white coats would contact potential users of the new technology to explain what benefits they might achieve from a customised computer system connected to the telephone communications network. Even looking back now, when one considers the inherent 'expandability' of the Electron, it would make perfect sense for BT engineers to have used it as an easily programmable "brain", and one to fit communication hardware to. Stripped of expansions like the Acorn Plus 1 and Acorn Plus 3, the Electron is actually smaller than a modern PC keyboard. So it was that Britsh Telecom got ahold of it, and its research and development centre at Martlesham built the expansion box before passing it to these eight bases that comprised the BT Merlin Division.

By June 1984, Electron User were announcing that the first deal had been done to use the Acorn Electron as a communication terminal and a spokeman (read 'salesman') was trumpeting that it as "something vital to any large organisation," and, with that in mind, "The potential market is enormous." That first customer was the NHS, and saw the Electron rolled out as a Acorn Merlin M2105 Healthnet Workstation. It is not known whether any of these variants still exist, and there is anecdotal evidence that the workstations were unable to cope when trialed in the busy wards of Charing Cross Hospital, dooming the venture to failure.

However, the Interflora project, beyond question where the specific machine we picked up was in service at some point, had much more success. Interflora was, at that time, a co-operative and one of the first 'chain' stores where, for example, you could ring up your local Interflora in Cambridge, and order flowers to be delivered to your girlfriend in Newcastle. In these pre-internet days, it was down to Cambridge to take the order, locate their nearest branch in Newcastle, ring them up, repeat the order over the telephone and also keep track of all the payments to satisfy their accountants. This meant in practice lots of assistants spending lots of time on the telephone. And lots of time spent on the telephone meant high telephone bills. To send a fax was, at the time, even more expensive.

The men in white coats at BT Merlin and the directors of Interflora got together to try and sort out how the computer revolution might strip out this repetition, and at the same time offer a more robust system of book-keeping. What they came up with was a specification for the expansion box which, when coupled with the Acorn Electron, became the Acorn Merlin M2105 Communications Terminal. Each terminal held in memory a set number of forms and these forms were instantly available from an EPROM inside of the computer. The assistant simply filled in the blank areas of the form; for example telephone number, type of bouquet, name of sender and address of recipient along with the message for the card.

When the order was filled in, the terminal would instantly dial the number of its contemporary in the Interflora shop nearest to the recipient. If the line was busy, it would wait 30 seconds then re-dial. When the two were connected, the receiving machine would call up the same form from its identical EPROM, and the sender would simply transmit the same data so the form was replicated in the receiver. The receiving machine was also set to automatically print out the order on a dot-matrix printer. This had the effect of eliminating the assistants needing to write down the original order, ring around the country and repeat the original order by phone and the new assistant also having to write out the order for a second time. The new technology meant that, 30 seconds after an order had been taken in one store, it had arrived in the store that would despatch the flowers. A revolutionary idea in the early Eighties.

Yet more stuff actually went on in each terminal as well. As each order arrived in a receiving machine, the date, the time and the cash amount for the flowers was extracted and placed into the battery-backed RAM of the expansion unit. When the RAM was 80% full, it would ring home automatically to the BT Merlin mainframe in Sleaford and transmit a message that it needed to have its contents downloaded that night. At midnight, the HQ PC's at Sleaford would work through a queue of terminals which needed to be emptied of their data, connecting to each one in turn and copying all the extracted data to their memory banks. In this way, all data from all stores ended up on one central machine, keeping all the accountants happy and allowing Interflora to compile statistical information from the results. Prior to this, a manual paper forms entry method had had to be used.

In a piece of forward thinking, certain other fail-safes were built in to the technology. For example, if the call to download at midnight was somehow missed for a certain machine, it would re-transmit the request the next day and, if there was still no response, when it got to 95% capacity, it would hook up to the mainframe, take control of it and force it to download the data at once. The on-board forms were also accessible over the telephone line, so that, when Switch cards became popular in the Nineties, one template form could be updated and, quite literally overnight, all the terminals had forms which allowed Switch cards to be used.

In all, says Bill, the system was enormously successful and it continued for over a decade. The machines themselves worked quietly in a corner of the flower shops, although some of the busiest stores had to have two of them simply to keep up with demand. The savings were staggering, both financially due to the 'telephone call' made between machines taking a maximum of 30 seconds, and in the auditing process, where the previously used paper-trail for orders was eliminated. Most of the problems the engineers had were with the dot-matrix printers which obviously had to exist in a flower shop environment and were being constantly splashed with water. He recalls upgrading the EPROMs on one occasion only and says, as each expansion unit was identical, engineers simply carried around replacements in their van, did tests on a broken machine to see if it was the Acorn Electron or the expansion box at fault, swapped the bit that was and sent the broken bit back to Acorn, or a BT factory, to either have it fixed or binned.

Aha, but what of those two ports on the back, and those mysterious claims made by 8BS about voice synethesis? At this Bill metaphorically shrugs his shoulders. "It's obvious that one of the ports is for the printer, but I don't think the other one was ever used in the field at least. But I've never heard of them using voice synthesis and, if we wanted to get into BASIC and play Birdstrike, we had to take off the expansion unit."

Unfortunately, Bill didn't see our appeals regarding the Merlin until he had binned his own copies of the instruction manuals, so even with all of this new information, we probably still have a lot more to learn about the Acorn M2105 Communications Terminal. As with the Electron itself, which seems to have had a shelf-life of roughly a decade, it was evidently around for a long, long time. The NHS trial runs, which Bill states were concerned with transferring patients between wards, were by all accounts a failure, having no real advantage over the system which was in place previously. Armed with all this fresh information, and the knowledge that several of you reading this have now gotten hold of your own terminal, perhaps we will all be hooking up together to order fake flowers from each other in the near future... Ahem. Or perhaps not, eh?