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Frequently Asked Questions (FAQs)

Can transponders be mounted on metal objects and read successfully?
One of the most frequently asked questions is how does UHF RFID work in the presence of metal?
With the correct mounting of Trolley Scan's EcochipTag, you can get 11 meters with just 1 watt of transmitted power!! The secret is to attach the transponders correctly to the object.
What is EcoTag(®)?
For passive transponders that operate on the RF energy radiated by a reader, energy efficiency and optimal energy transfer is critical. EcoTag® technology is a patented method of attaching an antenna to the integrated circuit that enables maximum energy transfer from the energy in space into the chip on the transponder. The technology also allows non conventional antenna systems to be used, such as an electrically short credit card sized antenna for 860-930 Mhz operation. These non-conventional shapes allow high volume mass production using techniques such as printing with a litho printing press for the antennas. As at February 2004, the lowest RF power single chip transponder produced by Trolley Scan in a credit card sized version needed just 200uW Rf energy in its 134 sq cm aperture to operate. This is 250 times less than that needed for a conventional circuit on a dipole, meaning smaller transmitters for the reader, longer battery life for the reader, and longer operating range. See EcoTag(®) features page
What is the best performance on low power so far achieved with EcoTag technology?
In Feb 2004 it is possible to read the credit card Ecochiptag(TM) tag at an amazing 6 meters while only using 0.3 watts (300 milliwatts)(Pt) of transmitter power with an 8dBi patch antenna. On just 1 watt users can read tags at 11 meters.
Why is EcoTag(®) an important development for RFID systems?
The EcoTag(®) version of Trolleyponder is over 250 times more sensitive than earlier technologies and competitive products operating in the 860Mhz to 930 MHz bands. This is particularly relevant for companies that wish to operate passive transponders in Europe or who wish to mark goods used for international trade that are also to be identified in Europe, as EcoTag is almost the only system that has sufficient reading ranges with the European restrictions to be practical. Europe allows only 1.6% of the reader power allowed on the US which drastically limits the operating range of non-EcoTag type transponders. The EcoTag technology has minimal cost implications in adding the extra sensitivity.
Can EcoTag(®) technology be added to other companies transponder systems under licence?
The EcoTag(®) package is a practical power enhancing technology for application to passive transponders together with their antenna systems. As such it is an independent package from the Trolleyponder protocol and can be made available to other transponder manufacturers under licence where they wish to operate their passive transponders within the European 0.5Watt effective radiated power(ERP) limits. Trolley Scan have now developed a datapack detailing this technology for those companies that wish to incorporate EcoTag into their designs.
How safe are Trolleyponder RF systems?
See article
Range versus power versus frequency for passive electric coupled tags
See article
Can RFID tags replace barcodes cost-effectively?
See article
How fast can Trolleyponder protocol scan 1000 items at a time?
See article
Can I buy samples of Trolleyponder transponders?
Trolley Scan, together with licensees of their technology, sell transpoders and readers for use in applications worldwide. Details of their small system can be found at the small system data page.
Why is Trolleyponder closer to a barcode replacement technology than other transponders?
Many different manufacturers produce many different transponder systems for many different niche markets. Trolleyponder is specifically aimed at becoming a barcode replacement system where fast, multiple article, low cost transponders systems are needed, with Electronic Article Surveillance features included if needed.
The technology is :
    • based on the most common silicon technology available;
    • the circuit is relatively simple;
    • the design allows wide tolerances in manufacture to give high yields and therefore low manufacturing costs;
    • the transponder has no tuned circuitry allowing the same circuit to be used over a wide range of operating frequencies and applications by just changing the antenna and packaging;
    • the protocol handles in excess of 400 transponders in the reading field at the same time;
    • the reading rate of transponders is fast;
    • Trolleyponder protocol has a 3 axis feature allowing tags top be read in all geometric orientations while only using a single frequency;
    • the transponders have advanced EAS features than can be commanded on, off or reactivated based on time;
    • the transponders are frequency agile making them suitable for world trade;
    • the transponders support a very large number range;
    • the transponders do not need unique identity numbers (counting of transponders with same identities);
    • the protocol offers one of the fastest reading rates for multiple articles available
    • the protocol is accurate giving very low error rates
    • the transponders use a single design for all applications and operating conditions, being a true one design fits all.
    • the transponders are low cost
What is controlling the selling price of Trolleyponder tags?
Although design can reduce the manufacturing cost of transponders, the selling price is driven by supply and demand. As Trolleyponder is a "Universal Identification technology", suitable for many different market niches, the selling price will only reduce as the higher priced application's needs are met. This is achieved by involving more manufacturers as suppliers, one of the functions of the Trolleyponder industrialisation process. This results in the early adopters of the technology providing solutions for the higher priced applications before competition increases. Although the first applications should use transponders that sell for less than a $3, the price should then start dropping as more competition enters the market to the tens of cents.
What is different between the name transponder and tags?
Transponders and tags refer to the same item, namely the electronic circuitry attached to the goods. Transponders were first invented during World War 2 when they were used to identify friend or foe aircraft for radar operators. Since then they have simplified in design to such an extent that they can now be used for tagging groceries in a supermarket, hence most probably causing the swing to the name tags. The name transponder also refers to radio equipment carried on satelites that rebroadcast signals received back to earth, such as with direct broadcasting satelite TV and telephone systems
What is Trolley Scan doing to encourage the industrialisation of Trolleyponder technology?
    • Trolley Scan realise this is a global project having application in many industries in almost all countries of the world.
    • Trolley Scan are providing the technology to companies throughout the world to enable them to become involved in a viable replacement technology for barcoding for their applications in their countries of interest
    • Trolley Scan are in process of protecting the technology with a series of patents, allowing only members of the Trolleyponder Development Group to exploit the patents
    • Trolley Scan have developed an information dissemination system for transferring information to licensees without the need for them to travel. The datapacks include sample designs and extensive technical information to allow them to impliment ands customise the design. Datapacks are kept up to date and technical support from Trolley Scan is available via email.
What about tin cans?
This is most probably the most asked question about RFID tagging systems
RFID transponders extract their operating energy and provide communications using electromagnetic propogation. These radio waves are cancelled on the surface of metal items and as a result short out the operation of tags that are attached to the surface of metal items.
    • For transponders that are mounted a short distance off the metal, say on the shrink wrapping of a six pack, the metal cans do not effect the transponder's operation in areas where the cans do not screen the incoming energy.
How does Trolleyponder EAS differ from conventional EAS tags?
Trolleyponder promises to offer a whole new range of features for EAS applications over the currently available tagging systems. The currently available systems generally indicate a presence of an item that has not been neutralised passing through the reader zone. The actual item is not uniquely identified except by passing the items one by one past the reader and working out which item has not been neutralised. The tags are generally a one switching only, being active until they are sold and then being neutralised, either by physical destruction, magnetic destruction or physical removal.
In Trolleyponder the item broadcasts its actual identity at the EAS reader, thereby giving the security the information about which item has not been neutralised, such as - sweater, mans, blue, size 42
In addition the tags can be switched between the various states by complex radio signals, allowing the same tag to be used for EAS and identification purposes with the goods manufacturer, the wholesaler, the retailer and even the home consumer as well as the transport operations between these users.
Trolleyponder EAS features can be turned on by command, off by command, and can be neutralised for a set time after which they activate again by themselves
What is the different between active and passive tags?
Passive tags extract the energy they need to operate from the energising field of the reader.
Active tags operate in lower energy reading fields and make use of an onboard battery to provide their energy.
Naturally passive tags are much cheaper as they do not have the cost of the battery, often much more than the tag's electronics.
Battery powered tags generally need a SLEEP mode when not in use to limit the energy they draw from the battery (in which case battery life times of 5 years are viable), and use a short exposure to an higher energy field to wake them up.
Tags operating below 1.6GHz usually can be made passive, while above these frequencies active tags are the norm to give reasonable reading ranges.
Does the use of metal trolleys and metal lined trucks effect the RFID system?
In a similar way that tin cans short out the operation of transponders on the metal surface, similar issues arrise when the container is metal. However in the situation of metal trucks and containers, the presence of metal can be an advantage as it contains the RF energy, but interaction between the direct waves and those that bounce off the walls do cause zones of varyiing energy density in different locations in the reading area. Trolleyponder have addressed this problem and with correct reader and system design, can wipe out these zones to get uniform operation in most areas within the container.
For trolleys a similar issue arises. However technology developments in trolley manufacture is slowly causing trolleys to be made out of plastic, which completely removes the problem. Four years ago when in South Africa the inventors demonstrated the first scanning electronic trolley, plastic trolleys were virtually not in existance ion the country. Now due to cost of manufacture and other issues, it is difficult to find a new metal tolley at any supermarket, showing how developments have changed the product availability.
Does one need to be a major electronics company to become a licensed manufacturer of Trolleyponder tags?
In the 1960's only companies that had their own computer scientists could own, operate and sell computers. Now computer systems are even available in the home. Although not yet to the same extent, similar evolutionary developments are happening in the RFID industry.
Although the large electronic companies have an advantage in industrialising this technology due to the availability of their own specialist staff, assembly equipment and capital, they also have their own impedances to committing full steam to such a project.
A small group of investors, assisted by specialist consultants, the designs from Trolley Scan, designers from the contracted foundry, and contract assemblers with a network of VARs would be a major player in such an insatiable market.
Trolley Scan have further simplified the process of transponder manufacture by providing a kit of parts to licensees who want to use low technology assembly methods. The kit comprises the chip and the antenna allowing the production of EcochipTag transponders.
If barcoding costs virtually nothing being printed on the packaging, why should there be an interest in using RF tags for retailing?
The overhead costs of getting manufactured goods into the hands of the consumer is not directly related to whether or not the labelling system is free. By putting RF tags into their products, benefits are achievable throughout the entire logistics and distribution chain. Just for the retailer with the ability of tags to be read at high rates, 4 meter reading ranges, volumes of multiple articles in excess of 400 items at a time,with RF penetration properties; his goods receiving is simplified and sped up, his stock taking of products in the store and display area are simplified to passing scanners past shelves, his checkout staffing and equipment is drastically reduced (some retaillers believe 70 checkouts can reduce to 5 with the increased throughput), and the retailer gets an advances Electronic Article Surveillance (EAS) system thrown in. In fact recent designs are now becoming available for a self service checkout with integrated credit card processing facilities and EAS for security.
Similar benefits are achieved by the manufacturer and wholesaler, including the features of EAS and the ability to use robotics due to the tagging system providing "vision" to the computers used for the robotics for picking.
What is tag pollution and specifically how does it impact airline baggage?
When tags of different manufacturers are attached to various goods and are exposed to a reader energising field, each of the tags will respond to that energising field and will attempt to communicate their identity to the reader. As an example consider an item of airline luggage. It might have a tag identifying the suitcase for the airport/airline/IATA, it might contain some books using an ISBN numbering system, it might contain some files used for a file tracking system, and it might have some clothes with imbedded laundry tags used for setting washing instructions for cleaning and ironing, it might contain a computer with an embedded tag for asset tracing, if fact the case might have 40 or 50 tags inside the case, besides the outer case tag. Many of these transponders will respond to the reader field, as they will collect energy and start operating. As the tags are low cost, they will not have expensive frequency rejection filters, and hence they will not be able to descriminate between different types of readers to suppress their response.
The important aspect of tag pollution is to realise that with such a large market with so many applications there will be many incompatible tagging systems, and system designer needs to ensure that the reader system can handle multiple transponder situations and reject any unexpected numbering systems or transmissions. Trolleyponder is ideally suited to such situations.
Why is 3 axis scanning important?
RFID tags use the communication of radio signals between the reader and the tag. The radio waves have a property called polarity, which needs to be the same or compatible between the reader and the tags for the
communication to take place. This polarity is generally related to the relative physical orientation of the tags and the readers relative to each other, for example their antennas both in a vertical or both in a horizontal geometric orientation. To now have tags attached to goods that are randomly orientated in the reading zone means that for some of the tags the orientation will be incorrect and communication will not take place.
Trolleyponder developments has addressed this problem and has applied for patents for features that allow full 3 axis scanning of multiple transponders at high scanning rates.
Who invented Trolleyponder?
Trolleyponder protocol was invented by Mike Marsh.
Mike Marsh and Trevor Hodson also invented a single frequency multiple axis scanning system for such transponders.
Mike Marsh is most probably the leading designer in the world for low cost transponder systems, having invented in 1991 the low cost system described in the patent "Electronic Identification System " which was demonstrated to the world on TV in 1994 by showing a trolley with 35 items being scanned in a couple of seconds. This technology is owned by the South African Government and is marketed under their trademark Supertag..
In 1994 Mike Marsh left the employ of the South African Government and later started the company Trolley Scan with Trevor Hodson to promote RFID scanning of groceries and other products where RFID scanning would be advantageous.
In 1998 Mike Marsh and Trevor Hodson filed their improved technology called Trolleyponder, which is a completely new set of intellectual property.
Mike Marsh is founder and editor of Transponder News , a respected web newspaper on transponder technologies.
Who invented EcoTag?
EcoTag was invented in South Africa by Mike Marsh. The first operational EcoTag transponder demonstration was built on the 27th April 1999. EcoTag has been protected by provisional patent applications.
EcoTag was developed in response to requests from Trolleyponder licensees operating in Europe who were restricted by the severe regulatory restrictions.
Why is Trolleyponder cheaper than most competitive technologies with such superior performance specifications?
Trolleyponder has been specifically designed to be a low cost transponder system while offering excellent performance. To achieve this it has been designed to be implimented in a single chip measuring less than 1mm2 with no external components, tuned circuits or coil antenna systems. Its antenna system is as a strip of metal foil. The skills needed to produce the transponders are based around available skills from silicon foundries around the world who make their services available to clients on contract..
What operating frequency is used by Trolleyponder?
Trolleyponder is a base technology and protocol that can operate at most frequencies in the radio spectrum. However particular benefits with regard to performance and pricing occur if it is designed to be used in the 200MHz to 1600MHz spectrum. The reason is that at these frequencies the technology is now available to produce the transponder as a single chip with a simple antenna. The technology is currently in high volume production for 869Mhz (EU/GSM countries) and 902-930MHz (US/Canada).
The following table lists expected performance versus frequency for passive tags- (performance does vary from product to product and these figures are typical)
Frequency Range Comments



Multiturn coil needed for transponder


1 meter

Simple coil antenna


20 meters

Fairly large simple dipole antenna


10 meters

Simple dipole antenna
(Trolleyponder preferred)


4-6 meters

Preferred antenna size/performance
(Trolleyponder preferred)


1 meter

High technology

Technology comparason

Why is Trolleyponder particularly suitable for labelling goods for international trade?
Trolleyponder designs utilise a property called frequency agility. This feature allows the tags to operate at different reader or operating frequencies without a loss of performance, a feature that is essential where transponders are used for labelling goods that are involved in international trade. As the different countries of the world each impliment their own spectrum allocation plans, plans that have evolved to meet their own particular needs, it is virtually impossible to get a frequency allocated for scanning that will be identical in different countries. As Trolleyponder does not use tuned circuitry in its design, and does not need specific operating frequencies, the tags will respond to readers that are at different operating frequencies in the different countries through which the goods pass. The addition of EcoTag technology to the Trolleyponder family is also relevant to this situation as EcoTag is able to offer good reading ranges in the US and Europe on very low power, yet keeping the cost advantages of a low cost passive tag.
What is the impact of EcoTag in an ISOcard format on existing passive RFID systems?
The reduction of size of the UHF transponder antenna to 80mm by 27 mm means that the physical size of the EcoTag transponder is now similar to that of the 13.56MHz smart label, yet offering much greater range

Trolleyponder®,EcoTag® and TinTag® are the TRADEMARKS of Trolley Scan (Pty) Ltd

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