Analog. Digital. What’s the Difference?
by Paul Wotel
Analog phone lines. Analog
signals. Digital security. Digital PBX. Analog-to-digital adapters. What does
it all mean? In the telecom world, understanding analog versus digital isn't
as simple as comparing one technology to another. It depends on what productand
in some cases, which product featureyou happen to be talking about.
Analog at a glance
As a technology, analog is the process of taking an audio or video signal (in
most cases, the human voice) and translating it into electronic pulses. Digital
on the other hand is breaking the signal into a binary format where the audio
or video data is represented by a series of "1"s and "0"s. Simple enough when
it's the deviceanalog or digital phone, fax, modem, or likewisethat
does all the converting for you.
Is one technology better
than the other? Analog technology has been around for decades. It's not that
complicated a concept and it's fairly inexpensive to use. That's why we can
buy a $20 telephone or watch a few TV stations with the use of a well-placed
antenna. The trouble is, analog signals have size limitations as to how much
data they can carry. So with our $20 phones and inexpensive TVs, we only get
The newer of the two, digital technology breaks your voice (or television) signal
into binary codea series of 1s and 0stransfers it to the other
end where another device (phone, modem or TV) takes all the numbers and reassembles
them into the original signal. The beauty of digital is that it knows what it
should be when it reaches the end of the transmission. That way, it can correct
any errors that may have occurred in the data transfer. What does all that mean
to you? Clarity. In most cases, you'll get distortion-free conversations and
clearer TV pictures.
You'll get more, too. The
nature of digital technology allows it to cram lots of those 1s and 0s together
into the same space an analog signal uses. Like your button-rich phone at work
or your 200-plus digital cable service, that means more features can be crammed
into the digital signal.
Compare your simple home
phone with the one you may have at the office. At home you have mute, redial,
and maybe a few speed-dial buttons. Your phone at work is loaded with function
keys, call transfer buttons, and even voice mail. Now, before audiophiles start
yelling at me through their PC screens, yes, analog can deliver better sound
quality than digital…for now. Digital offers better clarity, but analog gives
you richer quality.
But like any new technology,
digital has a few shortcomings. Since devices are constantly translating, coding,
and reassembling your voice, you won't get the same rich sound quality as you
do with analog. And for now, digital is still relatively expensive. But slowly,
digitallike the VCR or the CDis coming down in cost and coming out
in everything from cell phones to satellite dishes.
When you're shopping in
the telecom world, you often see products touted as "all digital." Or warnings
such as "analog lines only." What does it mean? The basic analog and digital
technologies vary a bit in definition depending on how they're implemented.
Analog lines, also referred to as POTS (Plain Old Telephone Service), support
standard phones, fax machines, and modems. These are the lines typically found
in your home or small office. Digital lines are found in large, corporate phone
How do you tell if the phone
line is analog or digital? Look at the back of the telephone connected to it.
If you see "complies with part 68, FCC Rules" and a Ringer Equivalence Number
(REN), then the phone and the line are analog. Also, look at the phone's dialpad.
Are there multiple function keys? Do you need to dial "9" for an outside line?
These are indicators that the phone and the line are digital.
A word of caution. Though
digital lines carry lower voltages than analog lines, they still pose a threat
to your analog equipment. If you're thinking of connecting your phone, modem,
or fax machine to your office's digital phone system, DON'T! At the very least,
your equipment may not function properly. In the worst case, you could zap your
communications tools into oblivion.
How? Let's say you connect
your home analog phone to your office's digital line. When you lift the receiver,
the phone tries to draw an electrical current to operate. Typically this is
regulated by the phone company's central office. Since the typical proprietary
digital phone system has no facilities to regulate the current being drawn through
it, your analog phone can draw too much currentso much that it either fries
itself or in rare cases, damages the phone system's line card.
What to do? There are digital-to-analog adapters
that not only let you use analog equipment in a digital environment,
but also safeguard against frying the internal circuitry of your phone, fax,
modem, or laptop. Some adapters manufactured by Konexx come designed to work
with one specific piece of office equipment: phone, modem, laptop, or teleconferencer.
Simply connect the adapter in between your digital line and your analog device.
That's it. Or you can try a universal digital-to-analog adapter such as Hello
Direct's LineStein®. It works with any analog communications device. Plus, it's
battery powered so you're not running extra cords all over your office.
The very nature of digital technologybreaking a signal into binary code
and recreating it on the receiving endgives you clear, distortion-free
cordless calls. Cordless phones with digital technology are also able to encrypt
all those 1s and 0s during transmission so your conversation is safe from
eavesdroppers. Plus, more power can be applied to digital signals and thus,
you'll enjoy longer range on your cordless phone conversations.
The advantage to analog
cordless products? Well, they're a bit cheaper. And the sound quality is richer.
So unless you need digital security, why not save a few bucks and go with an
analog phone? After all, in home or small office environments where you may
be the only cordless user, you won't have any interference issues.
Keep in mind, when talking
about digital and analog cordless phones, you're talking about the signals being
transferred between the handset and its base. The phones themselves are still
analog devices that can only be used on analog lines. Also, the range of your
cordless phoneanalog or digitalwill always depend on the environment.
Perhaps the most effective use of the digital versus analog technology is in
the booming cellular market. With new phone activations increasing exponentially,
the limits of analog are quickly being realized. Digital cellular lets significantly
more people use their phones within a single coverage area. More data can be
sent and received simultaneously by each phone user. Plus, transmissions are
more resistant to static and signal fading. And with the all-in-one phones out
nowphone, pager, voice mail, internet accessdigital phones offer
more features than their analog predecessors.
Analog's sound quality
is still superioras some users with dual-transmission phones will manually
switch to analog for better sound when they're not concerned with a crowded coverage
areabut digital is quickly becoming the norm in the cellular market.
What to buy?
The first thing to consider when buying analog or digital equipment is where
you'll be using it. If you're buying for a proprietary PBX phone system, you'll
need to get the digital phone designed for that particular system. Need to connect
a conferencer on your digital system? Opt for a digital-to-analog adapter. Shopping
for home office equipment? Most everything you'll consider is analog. Want an
all-in-one cellular phonepaging, voice mail, web? A digital cellular phone
will deliver it all. In fact, the only head-scratcher may be your cordless phone
purchase. Looking for security and distortion-free conversations in your small
office? Go with a digital 900 MHz or 2.4 GHz cordless phone. Using a cordless
at home? An analog phone will give you the richest sound quality and usually