There are three major types of phone systems available: KSU- Less phones, Key
systems and Private Branch Exchange (PBX) systems. Which type of phone system
you choose will depend on the amount of extensions you require and the features
your phone system needs to have installed.
Used KSU-Less phone systems
KSU-Less systems are usually more suited to companies that typically have
less than ten employees, or require less than ten extensions. That isn't to say
that all companies requiring less than ten telephone extensions can make do with a
KSU-Less system. It may be that you require more features which are only
available through either a PBX or Key phone system.
Requiring a far lower initial investment than the other types of business
phone systems, KSU-Less phones are specifically designed to include many of the
features usually only available through the implementation of a full small
office phone system.
KSU-Less systems can be easily unplugged and relocated, because they are not
permanently wired into your office. This portability allows you to treat a
KSU-Less phone system, much the same as any business machine, rather than a lost
You will need to ensure that any KSU-Less system you choose is compatible not
only with the type of wiring you have in your office, but also with any
accessories you may already have, such as: headsets, answering & fax
machines and modems. Because KSU-Less phone systems are relatively inexpensive,
they are not usually sold, installed, or maintained by telecoms vendors.
All of this means, you have to go out there and do not only the shopping
yourself but, also the installation and support. This is one of the two major
drawbacks of KSU-Less systems. The last thing any office needs is to be
concerned with the reliability and maintenance of its phone system. Another
drawback of KSU-Less systems is that they are more prone to something known as
crosstalk. This is where separate conversations may blend into each other. With
PBX, Key systems and Hybrid systems falling in price, it sometimes makes more
sense to invest in a full business telephone system, rather than become susceptible
to the risks of a KSU-Less system.
Used Private Branch Exchange (PBX) phone systems
If your business typically requires more than forty extensions, or your needs
dictate you need advanced functions from your business phone system, then PBX
systems are often the solution. PBX phone systems used to be extremely expensive and
only affordable by huge corporations with hundreds of extensions. Though this is
still the case for larger installations, the development of the technology
required has progressed to the point where a powerful, fully functional PBX
office phone system for a small business is able to fit on the top of a desk.
Nearly all these compact PBX phone systems come with all the features you
might want as standard. You pay a premium for the programmability and
flexibility that a PBX offers, but in most cases the price difference is not as
much as you may imagine between that of a less flexible phone system.
Used Key Phone Systems
Key phones systems are more typical in businesses that require five to forty
extensions. This type of telephone system uses a central control unit called the Key
System Unit (KSU) to provide features and functions that are not available using
ordinary phones. An example of this is: key systems using a KSU allow one
extension to call another in house extension, and prevents any other users from
picking up a line that is already in use. Key systems usually come as standard
with most features any business would expect, but in some cases they are often
less flexible than a PBX phone system.
Used PBX & Key Systems (hybrids)
Though Key and PBX systems have some different technical features, these
differences have become somewhat blurred over the past couple of years. Many Key
systems now offer features that were once only available to those who chose to
install a full PBX phone system. Some systems also operate internally as either
a PBX or Key system depending on the software installed. Sometime these systems
are often referred to as "Hybrid" phone systems.
Installation & maintenance of PBX and Key phone systems
PBX and Key phone systems require installation by fully trained and qualified
telecoms engineers. All outside and inside lines must connect to the PBX or KSU
cabinet. The installation and maintenance of one of these type of phone system
can be just as expensive as the phone system itself. In many cases you may be
able to use the existing phone lines available in your office, but unless the
phones you have been using are relatively new, they may not be compatible with
your new system, requiring you to purchase new handsets as well as the system
The Right Size Phone System
It is important that when buying a new office phone system, that you
know your requirements in advance. Knowing what features need to be included
with your new phone system will stand you in good stead when it comes to
negotiating with potential suppliers. When considering buying a new telephone
system for your business, there are two major factors that determine the size of
the system you require:
Lines. These are sometimes called trunks. The number of lines a system has
denotes the number of outside lines being used by a company.
Extensions. Most extensions will be made up of handsets. Though any equipment
that requires a phone line is classed as an extension. This includes fax
machines, modems, and credit card equipment etc.
It is important that you make a list of all the extensions and lines you may
need for your new phone system. Not forgetting some users may need more than one
line and multiple extensions.
With key systems, the size of a phone system is indicated as a combination of
both lines and extensions. For example a system that has 10 lines and 30
extensions will be shown as a 10 x 30 system.
With PBX phones systems, size is defined as a combination of lines and
extensions, called "Ports". The number of "Ports" is the maximum number of
connections that can be made to the phone system. These include outside lines
and inside extensions, as well as any other telephone system accessories.
When planning for a new business telephone system, you should take into account
the future expansion of your company, by foreseeing any extra needs at an early
stage. Even if your current phone system is handling calls well for the time
being, this may not be the case when any future expansion or improvements are
fully implemented. A good office phone system should be able to handle
expansion easily and in a cost effective manor. PBX phone systems allow you to
expand their capabilities, by adding new expansion cards, thus increasing the
number of ports available for use. A few key systems can be expanded by the
addition of another cabinet that is identical to the first.
When planning your new system it is important that you enquire about the
potential cost for the addition of more extensions or ports. It is important
that when choosing a new office phone system, you ensure expansion will come
not only easily but as affordable as possible for your company.