Bet recording pulses from different Ticket Issuing Machines (TIMs) were time division multiplexed onto every solenoid on the adding shaft. The system that I am most familiar with which is in the Eagle Farm Racing Museum, multiplexes sixteen TIMs onto a solenoid. There are earlier forms of scanners, the electromechanical multiplexers used with these systems, shown in images in the Photo Gallery, that multiplex 7 or 8 machines per solenoid.
George Julius presented a paper to the Institution of Engineers Australia on Thursday May 13th 1920 describing these systems, when a machine that had been built and tested capable of supporting 1,000 terminals and a sell rate of 250,000 bets per minute was demonstrated. This image is extracted from that paper. In a part of this paper George makes reference to several computing concepts that would not become commonplace industry jargon until decades later which in contemporary parlance translates to him describing a Large Scale, Low Response Time, reliable, Real Time, networked multi user system in 1920!. George's text from which this thought blossomed is presented below the previous image in the Photo Gallery accessible by clicking on this photograph and scrolling up to, and clicking on the FIG 9 icon. Following is relevant text to this Figure from George's paper:
It will be remembered that the extent of the movement of the epicyclic gear has to be controlled by the value of the ticket issued.
Each epicyclic gear has attached to it an escapement wheel mounted concentric with it, this wheel being very similar to the ordinary escapement wheel in a clock. These escapement wheels are themselves controlled by "dead-beat" escapements which are electro-magnetically operated from the ticket-selling machines. One such group is shown in Figure 12.
When a ticket is issued, an electrical impulse is sent through from the ticket-issuing machine, which, operating the correct escapement, allows the particular escapement wheel and the epicyclic gear attached thereto to be moved forward one tooth, the driving force being the coil spring. By varying the number of teeth on the escapement wheels the amount of rotation that accompanies the issue of any particular ticket can be varied. Thus if the movement of one tooth of a " twenty-tooth " escapement wheel is arranged to record the sale of a 10s. ticket, then one tooth on a "ten-tooth" escapement wheel will accurately record the sale of a 1 pound ticket.
In considering the application of the equipment to meet very much greater demands, it was apparent that the very large amount of gearing required under what may be called the Randwick system would be very costly both to install and to maintain. A modification of the system has therefore been developed, and may be briefly described as follows :-
In practice each issuing machine should be run at such a speed as will allow of the printing and issuing of tickets at the rate of 100 per minute, this being the maximum speed required. It has been found, however, that the electro-magnetic escapements can be installed to accurately pick up and record impulses at more than ten times this speed. The latest machines have therefore been constructed with one electro-magnetic escapement and epicyclic gear for each eight or ten ticket issuers. In this arrangement, however, allowance has to be made for the fact that the ten-ticket issuers may all issue tickets simultaneously on the same horse. Each issuing machine therefore is equipped with a device which stores up the impulse as soon as the machine starts to print a ticket, and this stored-up impulse is picked up by a distributor and passed on to the electro-magnet at a, speed that is slightly greater than the maximum speed of the issuing machines. Thus, if the ten issuing machines simultaneously start to issue a ticket on the same horse, during the issue of these tickets, the distributor picks up the ten impulses and delivers them in sequence to the electro-magnetic escapements. In such a case the electro-magnetic escapement would make ten beats in the time occupied by a selling machine in printing and issuing one ticket.
This modification has very greatly reduced the amount of adding gear required in the machine, as in the new type four, or at most six, escapements perform the same duty as was previously performed by the forty escapements in the Randwick type of machine.
This becomes of great importance in considering large equipments. A unit has recently been built to meet the conditions of betting on the largest French racecourses. On such courses it is necessary to allow for the installation of at least 600 selling machines, and the counters may be required to record the issue of a million tickets in half an hour.
The unit that has been designed and built will pick up the impulses from 900 windows selling tickets of various values between 10s. and 1000 pounds and will add these impulses and record them at speeds up to 250,000 a minute; that is, at a rate exceeding 4,000 per second. Such a speed is in excess of anything that can conceivably be required, but it must be remembered that although the issue of a million tickets in half an hour calls, for an average speed of issue of approximately 33,000 a minute, yet the issue of tickets is not uniform, and double this speed may be required during any particular minute.
Where installations of this magnitude are required, it is obvious that groups of selling machines have to be installed at various points on the racecourse, as it is impossible to bring the crowd to one spot. It is essential, then, that the crowd located at one group of selling machines should be kept informed of the state of the betting all over the course. In such cases, therefore, the impulses from the selling machines all over the course are transmitted to a central calculating equipment, this central equipment controls the operations of a number of indicators which may be located in any convenient positions, one set being placed near each group of selling machines. Thus, in an equipment to sell tickets on any of forty-two horses from 900 selling, booths, there would be 900 individual selling machines divided up into, say, twenty groups of forty-five in each group. There would also be forty-two central calculating units, one for each horse, and a grand total calculating unit. These in turn would control twenty groups of indicators, each group comprising forty-two indicators, one for each horse, and a grand total indicator. The whole installation therefore would consist of 900 printing and selling machines, forty-three calculating units, and 860 indicator units , the whole system being automatically controlled and, operated by the issue of tickets from the 900 selling machines. A unit of this capacity has, as before stated, been built, and thoroughly tested , and is available here for inspection by members.
The part of George's paper that is pertinent to this website is presented in the Mechanical Aids to Calculation Chapter of this website.
Thanks to the Institution of Engineers Australia for allowing reprints of any portion of the Mechanical Aids to Calculation publication.