Bloemfontein: Central University of Technology, Free State
Abstract
ThesisCommercial telephone answering machines are limited to some extent by
one or more of the following factors:
• limited facilities
• difficult to upgrade
• nonstandard telephone interfacing
• expensive
• lack of user-friendliness
• lack of dialogue and intelligence
The purpose of this study is to design an intelligent digital telephone
system which will overcome as many of the above-mentioned problems
as possible. The following features are proposed and will be discussed:
The use of a commonly available, but powerful, personal computer
processor and memory instead of the elementary and rigid processor and
magnetic tape storage units of the commercial telephone answering
machine . This allows the quick storage and retrieval of digitized
messages, each with its individual name, time and date stamp.
Using the personal computer's hardware and not duplicating the
processor and memory units allows a more cost-effective system
upgrade. Upgrades mainly consist of software changes and minor
hardware changes. This means that an upgrade does not implicate a total
hardware redesign. Standards as prescribed by the local switching network standards and
the Department of Post and Telecommunications, apply to this design
and are applicable for licensing of the product.
It is evident that the cost of this project and design is kept minimal by
not duplicating expensive components like the microprocessor and the
memory units, although these are used in the design. In this respect
upgrades are software orientated to further limit the costs.
The personal computer is equipped with a display which allows the user
to make easy selections in order to execute the required instructions or to
obtain information by using the help functions. This real-time help
function eliminates the need for a user manual.
Dialogue between user and personal computer over the telephone
network offers a simple method of delivering information without the
need for any extra equipment such as modems, keyboards or display
units.
The software used on the personal computer is designed in such a way
that the system is intelligent and capable of decision making.
Communication from the public telephone network is possible by using
the telephone keypad and Dual Tone Multifrequency (DTMF) signalling
