What Cellphone






If you want to use your mobile phone in your car you would be well-advised to install a hands-free kit. We've been  road-testing  two units, to see how they measure up against conventional car telephones



You're driving along the motorway, the phone in your pocket starts to ring, what do you do?  If you fumble about to answer it, and you're seen by the police, you could be charged with driving without due care and attention; you can't  pull over to the hard shoulder, ignore it and you defeat the object of having a mobile phone.


The solution is a hands-free car-kit, which enables you to take and make calls on the move, relatively safely. There's no need to pick up the phone, the caller is heard through a small loudspeaker, and a microphone mounted close to the driving position, picks up the sound of the drivers voice. Hands-free kits are now available for most portable phones, and prices, including fitting, vary between 200 and 500, depending on the make and model of handset, and the vehicle.


Car-kits have a number of additional benefits, not least an external antenna which improves range and signal quality -- compared with a hand-portable's own aerial -- minimising the number of dropped calls. Most car kits can also be fitted with a booster unit, which increases the phone's output power to the same level as a conventional car-phone. The cradle holds the handset securely, in a convenient position, and as a bonus, the majority of car kits will give the phone's battery a top-up charge whilst it's connected.


We've been evaluating hands-free car kits for two of the most popular portables, the Motorola Micro TAC II, and the Sony CM-H333. In fact there are three car available kits for the Micro TAC, the one we've been trying is the mid-range MMCKSTD deluxe kit which sells for around 290, excluding VAT and installation. The Sony kit is the QN333, it costs 255, (also ex VAT and installation).


Both set-ups were installed in the same vehicle, and connected to the Cellnet network, to enable us to carry out simultaneous, side by side comparisons. Our tests are designed reflect the sort of conditions and situations car phone users can expect to encounter in normal use, everything in fact from a weak signal to a car full of noisy children. By the way, more detailed descriptions of the two hand-portables used in this test can be found in our Buyer's Guide section, but for the purposes of this feature we're only concerned with the facilities that relate directly to in-car operation.



Both car kits include a cradle unit which contains the power adaptor, amplifier, control electronics plus connections to the car's power supply and antenna. They can be mounted in a variety of locations, but it's usually easiest  to have them on the vehicle's dashboard, or centre-console, within easy reach and line of sight of the driver.


The Motorola cradle connects to the handset by a curly lead and plug, which fits into the phone's accessory socket, the plug has a white identifying mark on one side which saves a lot of fumbling about. A set of pins in the base of the unit mate with contacts on the battery pack, these are for the charging facility. The handset is held in place by a spring catch, which is released by a button on the side of the unit. There are no controls, the cradle has a single indicator lamp, to show the power is on, otherwise all operations, including speaker volume are controlled from the phone. It's very simple to use, just plug in the connector and lock the handset into position. Switch-on and hands-free operation are all automatic, (provided the facility has been enabled on the phone's option menu). The phone can also be set to auto-answer, after two rings. Flipping the keyboard cover shut then open again switches the phone to handset operation. The phone switches off when it is unplugged.  Voice recognition and a power booster are available as optional extras.


The Sony phone is a simple push-fit into its cradle; a single plug, on the end of a curly lead, fits into the base of the phone. The plug is symmetrical, so you have to look closely at the contacts to see which way round it fits, this can be quite fiddly in dark or dull light. The cradle has an on/off switch, volume control  and power-on indicator, but no battery charging facility, which seems like an oversight. The cradle does have a mute function, however, to silence the car's hi-fi system, when the phone rings. The phone switches on automatically when it is inserted into the cradle, and hands-free mode is engaged. Removing the phone from its cradle and flipping up the ear piece changes it to handset operation.



Of the two phones the Micro TAC adapts far more readily to in-car operation, not just because of its hands-free features, but for the simple reason that it has an illuminated display and keypad. One of the most common complaints about the CM-H333 has been its unlit display; it's bad enough when used as a normal hand-portable, but in a car it's a disaster. Even in good light it's nigh on impossible to read the tiny display from more than a few centimetres, at night, in a car, it would be impossible, and potentially suicidal to try and dial out. It's certainly not something we'd recommend doing on the Micro TAC, the keys are very quite closely spaced, but at least you can see the numbers and display clearly.


In its favour the Sony phone does have a permanent signal-strength indicator, though as it's virtually invisible, along with everything else on the display panel, it's a mixed blessing. The signal strength display on the Micro TAC involves a couple of button presses; it would be more useful to have it on all the time, to warn of possible reception problems, before they occur.



We tried both phones in a number of locations with known reception characteristics. We drove to specific locations to make a series of test calls, and to negate the effect of any asymmetry in the antenna's radiation pattern, re-oriented the vehicle each time. In areas of good signal strength there was almost nothing to choose between the two set-ups which were equally reliable sending and receiving calls. As the signal strength dropped our control phone, an unkitted Technophone TP3 inside the test vehicle was the first to display a 'no-service' message. Both test phones continued to show a couple of signal levels bars but after another mile the Micro TAC was starting to struggle with intermittent service, whilst the CM-H333 was still showing two bars on its display. At this point calls on the Micro TAC became very noisy and unreliable, the Sony phone was still usable. After a further hundred yards the Micro TAC lost contact completely, the Sony phone could still be used, though quality was poor with frequent drop-out; eventually, after another hundred yards the CM-H33 gave up as well.


As far as in-car reception is concerned both phones were reasonably good; in each case the sound had a tinny quality, but that's no bad thing with speech, in a noisy environment like a car. Both units had plenty of volume in reserve, so they could still be heard, even with noisy road conditions, or a couple of rowdy kids in the back. There were significant differences in reception quality, at the other end. It would be fairly obvious to anyone in contact with either phone they were talking to a mobile but the Micro TAC sounded marginally clearer and a little less muffled than the CM-H333; on the debit side the Micro TAC audio tended to be very choppy, with sudden and frequent reductions in volume.



In spite of the reduced range the Micro TAC set-up emerges as the clear winner with more hands-free facilities and simpler operation; with the optional Class 2 booster we reckon it would pass muster as a fully-fledged car-phone. The Sony CM-H333 tries hard, and we cannot ignore the superior range, but it's way out of its depth as a car phone. At best the car kit is a handy of staying in touch when you're on the road but it's by no means an alternative to a proper car-phone, or more sophisticated set ups, like the Micro TAC.



Both of our test phones were installed by Carphone Warehouse, at their Paddington Green fitting centre, just off London's Edgware Road. The vehicle used was a Mitsubishi Shogun, which amongst other things has ample room for two phones and has been home to several phones in the past, so it is a known quantity.  Jason, the engineer assigned to our vehicle, warned us that a normal installation can take up to two hours; two phones would take a good deal longer, even though he had assistance. In fact it took the two engineers only an hour and twenty minutes from deciding the positions for the cradles to switching on and testing the two phones!


The first job was to fix the aerials, two glass-mounted quarter-wave Algon Clics were used, sited on the offside of the vehicle. Mounting the cradles took around fifteen minutes, the rest of the time was spent connecting everything up, removing and replacing panels, carpet and trim, to hide the cables. The Micro TAC cradle is by far the neatest design with all of the cables ready wired and emerging from the underside of the unit. The Sony cradle has a row of five connectors along the bottom edge. Most installers tape all the cables together and tuck them out of sight as close to the unit as possible but however they're arranged it is going to look untidy. As a matter of interest, Jason told us that  Jaguars and Porsches are the worst cars to work on, due to the amount of fiddly and delicate trim that has to be removed.


The installation went very smoothly, after a final check on the aerials, and tidying up the car, we were back on the road and on the air in just under two hours. After two weeks the only problem to have arisen concerned the Micro TAC's microphone, which became detached from the trim above the drivers door, hardly surprising considering it was only help in place by double-sided sticky tape.


By the way, you never know who you'll bump into at the Carphone Warehouse fitting centre. According to our man Jason, there's a always steady stream of music and showbiz celebs passing through the workshop, in fact we missed Lennox Lewis by just a few hours, he was there getting his third carphone installed in a stretch limo.



R.Maybury 1992 0811



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