BOOT CAMP 047
MODEM MADNESS PART 2
The subject of PC modems bring to mind the story of the US
patents clerk who in eighteen something or other confidently declared that
everything that could be invented, has been invented… No sooner are we told
that modems and the telephone network have reached the limit of their data
handling capabilities, along comes a new standard or tweak that makes them go
Faster modems and connections mean lower telephone bills and
on-line charges and less frustration, waiting for things to happen. So how fast
can your PC go? A standard BT analogue telephone line is theoretically capable
of two-way data transfer rates of up to 33,600 bits per second (33.6kbps or
33k6); that's an acceptable speed for Internet browsing so accept nothing less
if you're buying a new PC or modem.
The speed at which data can be sent from your PC to the
exchange and on to your Internet Service Provider (ISP) -- over a normal
analogue line -- is pretty well fixed at 33.6k. However, it is technically
possible for data to be sent back to you at a much higher rate -- up to
56,000bps (56k) -- providing your local exchange has been converted to digital
operation. In practice the speed will probably be a bit slower than that -- 45
to 48kbps is a good average -- but it is a decent step up from 33.6k, particularly
as Internet surfing involves mostly downloading information.
Until very recently there were two competing standards for
56k modems, known as K56Flex (developed by Rockwell) and X2 (from US Robotics),
and this caused a great deal of confusion. However a new 56k standard, called
V.90 has now been ratified by the International Telecommunications Union (ITU).
The problem is not all ISP's have modified their equipment to V.90 standard and
not all 56k modems will be compatible without an upgrade. The best advice, if
you're thinking of buying a new super-fast modem, is to wait for a month or two
for the dust to settle, the standard to become properly established, and your
ISP to be actually using it.
If on-line time is money in your business, or you're just impatient
and you want an even faster connection then there are two alternatives: ISDN
and BT Highway. ISDN or the Integrated Services Digital Network is a dedicated
digital telephone line that can support connections of 64kbps; a single ISDN line
can be upgraded to two 64kbps channels, or one 128kbps channel. ISDN tends to
be quite expensive and better suited to business users. A single channel ISDN line
costs from £117 to install (all prices quoted include VAT), upgrading to
2-channel ISDN (ISDN2) costs a further £94. On top of that there is a quarterly
rental charge of £90 (assuming you make at least £67 worth of calls each
quarter), call charges are at normal BT rates. You will also need a device
called a Terminal Adaptor (the ISDN equivalent of a modem) connected to or
fitted inside your PC; prices start at around £70 for basic models.
BT Highway is a 'domestic' variant on the ISDN theme and
involves converting your existing analogue line to digital operation. The basic
option works out at £136 to have the Home Highway box installed. This has four
sockets; two are for an analogue phone and fax machine etc., and two 64k (or
one 128k) digital lines, for PC connections. Subscribers get two new phone
numbers in addition to their existing analogue phone number, which they can
continue to use. Quarterly rental for regular users comes to £47 and calls are
charged at normal BT rates. Once again the PC will need to be fitted with a
terminal adaptor to make use of the digital connection.
It's worth noting that not all ISP's support ISDN
connections, so check first. Everything
else you need to know about ISDN and BT Highway can be found at the web sites
The chances are you already have a modem connected to your
Windows 95/98 computer, pretty well all new PCs come with one these days, but
just in case you haven't got one, or you want to upgrade to a faster model,
here's what you do.
With the PC switched off install or connect the modem. Internal
modems plug into a free EISA/ISA expansion slot on the motherboard. Observe the
usual precautions regarding static electricity; the normal procedure is to
leave the PC plugged into the mains socket, but the outlet must be switched
off. Before handling anything always touch the PC's metalwork, to dissipate any
static charges, or wear an anti-static wristband (obtainable from most PC
hardware dealers for a couple of pounds).
External modems connect to the one of the PC's serial communications or
'COM' sockets. Most modems come with a suitable lead and adaptor (PCs can have
9 or 25-pin COM sockets). You will also need to connect and plug in the
external mains power supply, switch it on, and then switch on the PC.
In theory Windows 95 and 98 should identify the new modem
during the boot up process and install and configure it automatically. If not,
when Windows 95/98 has finished loading, open Control Panel (Start then
Settings) and double click on the Add New Hardware icon. This will open the New
Hardware Wizard that will take your through the installation routine. If your
new modem came with an installation disc make sure you have it to hand; you may
be prompted to use one of the Windows 95/98 drivers though in general it is
better to use the one from the manufacturer as this will be more up to date.
You probably won't be surprised to know that even faster
connections should be possible in the not too distant future. Digital
satellites have the capacity to download data from the Internet -- via a
set-top box or digital TV -- to your PC at up to 400kbps, though your PC will
still need to be connected via a modem to a normal telephone line, to request
the information. Looking a little further ahead fibre-optic cable systems can
carry data at up to 40 million bits per second (40Mbps), by which time pigs
will be flying and there will be something worth watching on Channel 5….
Next week, designing Christmas cards on your PC
BITS PER SECOND (bps)
The number of bits per second a serial communications system
can handle determines how fast information can be conveyed from one point to
EISA/ISA EXPANSION SLOT
Extended Industry Standard Architecture, type of connector
on a PC motherboard, used for expansion or adapter cards
The most recent technical standard for high-speed analogue
modems, the current standard for 28.8k and 33.6kbps modems is V.34
Windows 95 and 98 has a useful little utility called System
Monitor that allows you to visually check the data throughput of an external
modem, in real time. It can be found by clicking the Start button, then
Accessories and System Tools. Open System Monitor and click on the Edit menu
then Add Item. Select Dial Up Adapter from the list in the Category Window and
Bytes Received/Second and Bytes Transmitted/Second in the Item Window, then OK.
(Note, System Monitor is not installed by default so you may have to load it
from your Windows CD-ROM using Add/Remove Programs in Control Panel).