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ON THE CARDS
INTRO
With a mobile phone and a laptop you can surf
the net, fax and e-mail anywhere in the world... Well, that’s the theory! Rick
Maybury has been looking at the practicalities of mobile data communications
COPY
When the first digital cellular phones
appeared way back in 1993 -- it seems like an awfully long time ago -- one of
the most enticing features was the promise of mobile data communications, with
the facility to send and receive faxes, surf the internet and pick up e-mail,
via a laptop PC. The reality has been somewhat different. Initially only a
handful of phones were up to the job, moreover the additional hardware needed
was expensive and could be difficult to use. Gradually that has changed, more
new phones are now ‘data compatible’ but the biggest advances has been in the
cost, availability and performance of PC Cards.
A PC Data Card is the vital link, that
enables a computer to communicate with a mobile phone. These credit-card sized
devices are based on a common technical standard, set by the Personal Computer
Memory Card International Association or PCMCIA. The PCMCIA format was
originally developed for memory expansion modules, and most laptop computers
built within the past five years have one or more ‘PC Card’ slots, as they’re
known nowadays. The standard has evolved to enable a wide range of peripheral
devices to plug into portable PCs, including PC Data Cards for mobile phones.
The one’s we’ll be looking at are all are all ‘Type II’ cards, which are 5mm
thick.
It’s easiest to think of a PC Data Card as a
type of modem, though they operate in a slightly different way to the modems
used to connect a PC to a fixed phone line or ‘land-line’. However, the way in
which they work is, and should, be irrelevant to the user, who simply wants the
same kind of flexible communications facilities available on their desktop PC.
In an ideal world that would be possible, but
there are several differences to be aware of. The most obvious one is the speed
at which data can be sent over a mobile phone link. The basic GSM specification
for data transfer is 9,600 bits per second (bps) which is a good deal slower
than the current norm of between 14,800 to 33,600 bps for budget PC modems on a
fixed line, and well below the maximum download speed of 56,000 bps, that is
possible on the latest top-end models connected to some on-line services.
Nevertheless, 9,600 bps is adequate for faxes, e-mail, word-processor files and
SMS text (short message service); it only starts to be a problem with complex graphics-based
material, like the internet World Wide Web, when it becomes painfully slow.
It is possible to speed up data transfer
rates using a range of data compression systems, the commonest being MNP
(Microsoft Network Protocol) and V.42bis, (or a combination of both). Whilst compression can speed up the transfer
of raw data to 33,600 bps and beyond, it doesn’t work well on data that has
already been compressed (Zip files, etc.).
Another difficulty with mobile data
communications is the quality -- or otherwise -- of the signal. In areas of
poor coverage data links can be very slow and unreliable, moreover using a
mobile data system on the move is inadvisable as interruptions and fluctuations
in signals strength can result in the call being dropped, and data corrupted.
Normally error correction is carried out by the data card and its associated
software, this is known as ‘transparent’ mode, however, some data cards can
operate in a ‘non-transparent’ mode, where error checking is carried out by the
network. If problems are detected the data is re-sent. The trade-off is speed,
and on a weak or unreliable line, throughput can be very slow indeed.
If you’re sold on the idea of mobile data
communications the first thing to do is make sure you have the necessary
hardware. Generally speaking you don’t need an especially fast or powerful
portable PC for faxing and e-mailing, you may be able to get away with a nimble
386, but it’s probably better to think in terms of a 486 or low end Pentium
model, with at least 8Mb of RAM and a fair amount of free hard disc space.
Needless to say it must have a vacant Type II PC card slot, and run Windows 3.X
or 95.
A number of personal digital assistants
(PDAs), palm-top or hand-held PCs also have PC Card slots, (or optional
adaptors). Because of the different operating systems these products use the
range of communications packages is a lot smaller, however the situation is
changing. The first hand-held PCs using the new Windows CE (compact edition)
operating systems are coming on to the market, most of them have PC Card slots,
and communications software installed. One or two models have GSM connectivity
built-in, so if you’re in the market for a pocket PC it may well be worth
waiting for a few weeks longer, to see what becomes available. Owners of Apple
Mac laptops are also catered for, but the choice of software is narrower.
Just before we went to press Nokia launched
their new Cellular Data Suite software package. This is in effect a virtual
modem or data card, designed to run on any Windows 95 PC or laptop. All the
clever stuff is done in software, with the phone connecting to the PC via the
serial port. Fax and data operate at up to 9,600 bps, and it comes complete
with a connecting cable for the phone. The retail price is likely to be in the
region of £99, which compares very favourably with current hardware solutions.
Unfortunately it was not possible to test the package in time for this issue,
but if it lives up to expectations it could be a serious alternative to a PC
Data cards.
Next the phone. The critical feature is
obviously data compatibility, but we also need to say a word or two about the
networks. Thus far we have only mentioned the GSM systems operated by Cellnet
and Vodaphone, but there are two other digital networks in the UK -- Orange and
One-2-One. These work on a higher frequency band and use the PCN system, which
also support data communications. However, there’s a few points to bear in
mind. The choice of data compatible phones for both PCN networks is much
smaller than GSM. Secondly coverage. Orange is catching up with Cellnet and
Vodaphone but there are still some sizeable gaps around the country; One-2-One
has even more ground to make up and probably isn’t worth considering if you
live any distance from one of the major conurbations, or you intend to travel
around a lot.
Outside the UK the picture is bleaker still.
Cellnet and Vodaphone have full or partial fax and data services with between a
third and half of the countries they have roaming agreements with, but coverage
can still be patchy outside of large cities, check with your service provider
for the latest details. You can more or less forget overseas data
communications with Orange and One-2-One at the moment, though both companies
say they’re working on it. Orange are making good progress and may be worth
considering within the next year or so.
Now we come to the actual cards. We have
elected to look at PC Data cards offered by the major phone manufacturers,
rather than try to list all of the available products. That’s something we’re
considering for a future issue, when we’ve had the chance to figure out an easy
way to present all of the permutations and compatibility issues. If you’re in
the market for a PC Data card our advice is to look at the phone manufacturer’s
wares first, at least you know they’re going to work with the phone. There’s
certainly nothing wrong with accessory company’s cards, a lot of them come out
of the same factories as manufacturers own models, and they’re often cheaper,
but it’s a good idea to check, and then double check compatibility, before you
part with the plastic.
Finally, on a general note speed is obviously
a consideration, if you’re planning to use the data card for anything other than basic fax and
e-mail, but remember the maximum quoted speeds are only rarely attainable, and
that’s under ideal conditions. Twin cards, with both mobile phone and
fixed-line connectivity are well worth thinking about, especially if you’re
likely to be travelling abroad, where you can’t rely on a local mobile data
service being available.
ERICSSON
Make/model: DC23
Type: GSM/PCN data card
Phones: 318,
388 and 337 (fax not possible on 337)
Street price: £350
Fax speed: 9,600
bps
Data speed: 38,400
bps (with compression)
Software: Trio
DataFax Lite
Make/model: DC33
Type: twin GSM/PCN/fixed-line data card
Phones: 318,
388 and 337 (fax not possible on 337)
Street price: £470
Fax speed: 9600
bps
Data speed: 38,400
bps (with compression), 192,000 bps (land-line with compression)
Software: Trio
DataFax Lite
Contact: Ericsson
Consumer Helpline (0990) 237237
MITSUBISHI
Make/model: FZ-1405078
GSM Data Card
Type: GSM/PCN data Card
Phones: MT20D, MT30
Street price: £350
Fax speed: 9600
bps
Data speed: 14,400
(with compression)
Software: BVRP
Fax Tools
Contact: Mitsubishi
(01707) 278621
MOTOROLA
Make/model: CELLect
1+
Type: GSM/PCN data card and phone holder
bracket for laptop PC
Phones: all
data compatible models (specify model for correct lead)
Street price: £250
Fax speed: 9600
bps
Data speed: 9600
bps
Software: BVRP
Phone Tools
Make/model: CELLect
2
Phones: all
data compatible models (specify model for correct lead)
Type: twin GSM/PCN/fixed-line data card
and phone holder bracket for laptop PC
Street price: £300
Fax speed: 9600
bps
Data speed: 33,600
bps (with compression), 14,800 bps (fixed-line)
Software: BVRP
Phone Tools
Make/model: CELLect
3
Phones: all
data compatible models (specify model for correct lead)
Type: twin GSM/PCN/fixed-line data card
and phone holder bracket for laptop PC
Street price: £386
Fax speed: 9600
bps
Data speed: 33,600
bps (GSM and land-line)
Software: BVRP
Phone Tools
Contact: Motorola (01256) 316800
NOKIA
Make/model: Cellular
Data Card DTP-2
Phones: all
data compatible phones (specify model for correct lead)
Type: GSM/PCN data card
Street price: £300
Fax speed: 9600
bps
Data speed: 9600
bps
Software: Set-up
disc,
Make/model: Cellular
Data Suite
Phones: all
data compatible phones (specify model for correct lead)
Type GSM/PCN data card emulation software
PC any Windows 95 PC
Street price: £100
Fax speed: 9600
bps
Data speed: 9600
bps
Software: SMS,
Fax and utilities
Contact: Nokia
Mobile Phones (0990) 002110
PHILIPS
Make/model: Mobile
Data Card
Phones: Fizz,
Spark and GSM Genie
Type GSM/PCN data Card
Street price: £130
Fax speed: 9600
bps
Data speed: 9600
bps
Software: Mobile
Data Communications Suite
Make/model: Twin
Data Card
Phones: Fizz,
Spark and GSM Genie
Type: twin GSM/PCN/fixed-line data card
Street price: £230
Fax speed: 9600
bps (GSM), 14,400 bps (fixed line)
Data speed: 38,400
bps (with V.42bis compression, fixed line)
Software: Mobile
Data Communications Suite
Contact Philips
Consumer Communications 0645 282828
SONY
Make/model: Mobile
Connector QN010PCM
Type: GSM/PCN data card
Phones: DX1000
Street price: £300
Fax speed: 9600
bps
Data speed: 9600
bps
Software: Trio
DataFax Lite, Winfax Lite
Coming soon for the CM-Z1
Make/model QN022PCM
Type GSM/PCN data card
Phones CM-Z1,
DX1000
Street Price £TBA
Fax Speed 9600
bps
Data Speed TBA
(V34 compression)
Software TBA
Contact: Sony
Customer Information (0990) 111999
BOX COPY 1
BUNDLED SOFTWARE
Most PC Data Cards outfits include one or
more communications software applications, usually for fax SMS and data, and
almost always for the IBM PC; MAC versions may be available but you’ll normally
have to ask. They vary quite widely in sophistication and flexibility, however,
as far as the PC is concerned, the data card is simply a modem, so you should
be able to use your existing comms software. Settings will almost certainly
need re-configuring, particularly if the PC has been used with a normal modem.
Some applications may require additional drivers or patches; it’s always worth
checking the ‘Readme’ file that should be on the installation and set-up
diskettes that accompany most cards.
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Ó R. Maybury 1997 1806
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