Page 139 - DMGT505_MANAGEMENT_INFORMATION_SYSTEM

Management Information Systems

Notes VoIP (Voice over IP) is an IP telephony term for a set of facilities used to manage the delivery of
voice information over the Internet. VoIP involves sending voice information in digital form in
discrete packets rather than by using the traditional circuit-committed protocols of the Public
Switched Telephone Network (PSTN). A major advantage of VoIP and Internet telephony is that
it avoids the tolls charged by ordinary telephone service.
Companies providing VoIP service are commonly referred to as providers, and protocols which
are used to carry voice signals over the IP network are commonly referred to as Voice over IP or
VoIP protocols. They may be viewed as commercial realizations of the experimental Network
Voice Protocol (1973) invented for the ARPANET providers. Some cost savings are due to utilizing
a single network - see attached image - to carry voice and data, especially where users have
existing underutilized network capacity that can carry VoIP at no additional cost. VoIP to VoIP
phone calls are sometimes free, while VoIP to PSTN may have a cost that’s borne by the VoIP
user.

There are two types of PSTN to VoIP services: DID (Direct Inward Dialing) and access numbers.
DID will connect the caller directly to the VoIP user while access numbers require the caller to
input the extension number of the VoIP user. Access numbers are usually charged as a local call
to the caller and free to the VoIP user while DID usually has a monthly fee.

Notes Hamon Corp., a company that manufactures devices for control of air pollutants,
noticed a significant increase in telephone costs as its staff grew from 130 to 500. The firm’s
CFO decided to subscribe the company to a VOIP service. The company’s telephone cost
decreased by at least $ 12,000 per month.

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Caution There are also DIDs that are free to the VoIP user but chargeable to the caller.

Task Discuss the use of VOIP protocols.

Self Assessment

Fill in the blanks:
5. .................................... is a standard for software that digitizes and compresses voice signals
and transmits the bits via the internet link.
6. Voice over Internet Protocol (VoIP) is a general term for a family of ....................................
technologies for delivery of voice communications over IP networks.
7. Companies providing VoIP service are commonly referred to as ....................................
8. Protocols which are used to carry .................................... signals over the IP network are
commonly referred to as VoIP protocols.
9. There are two types of PSTN to VoIP services, .................................... and access numbers.

7.4 RFID

Radio-frequency identification (RFID) is the use of an object (typically referred to as an RFID
tag) applied to or incorporated into a product, animal, or person for the purpose of identification

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