Analog. Digital. What’s the Difference?
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 product—and in some cases, which product
feature—you 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 device—analog or digital phone, fax, modem, or likewise—that 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 so much.
The newer of the two, digital technology breaks your voice (or television)
signal into binary code—a series of 1s and 0s—transfers 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, digital—like the VCR or the CD—is 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. Read on.
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 systems.
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
current—so 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 technology—breaking a signal into binary code and
recreating it on the receiving end—gives 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
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 phone—analog or digital—will 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 now—phone, pager, voice mail, internet access—digital
phones offer more features than their analog predecessors.
Analog's sound quality is still superior—as some users with dual-transmission
phones will manually switch to analog for better sound when they're not
concerned with a crowded coverage area—but 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 phone—paging, 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 enough range.