These days, companies recognise the need to embrace today’s technology if they are to move forward and the modern PDA device that can be had off the shelves of most supermarkets provides the perfect solution. In fact, most drivers already own modern phones that can do this providing they can download the necessary software "app". There are pro's and con's but overall the PDA solution wins hands down.
Some argue they can't afford to pay the airtime charges associated with such devices but do the sums! Given a sim cost about £3 per month, it would take twenty-eight years to match the cost of a conventional data unit, which by that time would be completely obsolete.