An in-depth, qualitative analysis and comparison of five telephony systems models.

After exhaustive research on the five main telephony systems models, the following
illustrates main points of each model and delves deep into each model's positive
and negative attributes.

The five telephony systems are explored in order of least advanced to most.

Plain Old Telephone System: POTS is the original telephony system, a
throwback to days when you would share a malt with your best gal and dance to
Sinatra on your victrola.

POTS work thusly: telephone wires link a carrier to a business, allowing telephony
services to take place. All phones inside the building are connected to this central
wire.

Positive attributes: - Little about POTS has changed since its first incarnation as two tin cans
connected by string, but if it ain't broke, why fix it? All non- VoIP telephony systems
are based on POTS.

Negative attributes: -Features are limited by telephone wires; POTS cannot offer the advanced
features found in VoIP telephony systems. -Offers little flexibility, something dynamic businesses need from a telephony
system: POTS is entirely dependent on the carrier. -More expensive than other models, as businesses are charged monthly for
each call feature they use.

Key Telephone System: KTS is an updated version of POTS; telephone
wires stop at a business's KTS switch instead of going directly to a phone, as is the
custom with POTS.

Positive attributes: -Less expensive than POTS, including more features for less money. -Expandable, a definite plus in today's fast- passed world.

Negative attributes: -Akin to POTS, features are limited by transmission over telephone wires.

Central Exchange: CENTREX is similar to PBX, but CENTREX is not
privately owned. Instead, CENTREX is owned by a telephone company, who then
sells lines and features to a business.

CENTREX is often used by business or companies looking for a temporary solution
who plan on later switching to PBX or VoIP.

Positive attributes: -Carrier is responsible for line maintained, making CENTREX less expensive
than other models. -Provides drastically more features than POTS. -Good solution for companies that need several extentions with many
features, but a PBX is too expensive.

Negative attributes: -Each line is more expensive than using POTS.

Private Branch Exchange: PBX does away with telephone carriers; a PBX is
owned by an individual business, providing telephony service to that business
exclusively.

Positive attributes: -Provides dedicated service unencumbered by telephone carriers. -Offers many more features than POTS. -Businesses can easily make the transition to VoIP.

Negative attributes: -High maintenance cost.

Voice Over Internet Protocol: VoIP is the most advanced telephony
systems available, offering advanced features and powerful applications not found
in other systems. This is possible because data and voice are transmitted on the
same cable.

Positive attributes: -Eliminates the toll and monthly fees found in other systems. -Offers advanced features than can help improve efficiency and productivity. -Increased reliability of the network. -One line for both data and voice greatly reduces maintenance.

Negative attributes: -Equipment costs are higher than other models