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With TETRA systems now deployed in more than 114 countries, demand is growing for reliable and innovative accessories to extend the usefulness of radio terminals in a widening range of applications. Tim Guest takes a look at a few of the options available Whether a fire service, airport operator, industrial concern or public transport authority, TETRA users face demanding scenarios in which their communications systems must operate, and operate without failure. The TETRA Association’s document, ‘Wireless Public Safety Communications Network – planning considerations’, warns: “The terminals used in public safety networks also often have unique requirements. They need to be extremely robust and often must be able to operate in hostile environments, including high heat, extreme cold, dust, rain and water and not to forget under extreme ambient noise levels. “They need very high audio output and must be extremely reliable, being able to withstand shock, vibration and other rugged treatment. They may need to be able to operate in explosive atmospheres.” It follows, therefore, that any associated accessories must meet the same exacting standards as any of the terminals they are intended to support. Alternative views Motorola, currently the largest manufacturer of TETRA radios in the world, and Sepura, the most prolific manufacturer of handsets for public safety, both offer extensive accessory portfolios to support their own handsets. With a growing circle of other manufacturers, such as Cassidian, they contribute to a pool of some 40 or more different handsets on the market suited to a wide range of applications – for which a choice of both OEM and non-OEM accessories is available in support. A key strength of the TETRA standard has been the concerted effort to achieve interoperability between network infrastructure and user equipment that will provide end users with a freedom of choice. Any product entering service, be it a handset or accessory, should meet exacting industry standards. But this is where OEMs are likely to argue, as Sepura did when approached by TETRA Today, that it is better or safer to opt for an accessory direct from them or from a licensed reseller/distributor, rather than from an unknown source. “All Sepura original accessories are tested for full compliance to international EMC and R&TTE directives”, stressed a spokesperson, adding: “All genuine Sepura audio accessories are tested to comply with acoustic shock regulations and incorporate H+SE [health and safety] guidelines on use... All of our products are subjected to full environmental and mechanical testing to ensure durability and reliability.” However, many reputable non-OEM makers also make sure their products meet a range of industry standards – while other makers, often from China, may push largely untested products into the marketplace with a low price tag. Peace of mind If the end user wants total peace of mind in any accessory purchase, the OEM’s portfolio should certainly be considered, and this is certainly the point coming across loud and clear from Sepura: only the branded accessory can be guaranteed to meet all the exacting standards and, in turn, be suitable for the demands of its public safety customers. “Of course an OEM will promote its own brand in such a way”, I hear you say. Well, for manufacturer whose customers operate solely in the public safety sector it stands to reason: no-one wants a battery or an earpiece to fail at a critical moment that could, conceivably, cost lives. Building a solution At Motorola, Iain Ivory, senior solutions marketing manager for Motorola Solutions EMEA, offered this advice: “When purchasing accessories, users need to be aware that they are buying part of a solution – they cannot treat the accessory as a separate part, and that it will not affect the overall performance. To help put this into context, think about something as everyday as a portable music player: many of us have bought a new set of earpieces, only to find the audio poor. Do we blame the player, or the earpiece? “Top of the [TETRA] list are often audio accessories”, he went on. “But we have seen items from well-respected third parties delivering poor performance, with the customer not knowing whether to blame the radio or accessory. For this reason Motorola runs its Application Partner Programme. Selected specialist suppliers work with Motorola to ensure optimal configuration of the radio, accessory and software settings, so the customer gets the best solution. “Another example of how poor third-party accessories can impact a radio is batteries. Many companies can build a battery that fits a radio, but can it meet the demands of TETRA operation? Modern linear transmitters can draw large peak currents, for example when first keying up. Poorly-designed third-party batteries can mean that at these times the internal resistance of the battery reduces the terminal voltage to the point that a radio will reset!”
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