Computer Networking & Security

Archive for August, 2009

The iPod is one of the icons of the 21st century. The little pieces of plastic and metal with the ubiquitous white earphones have become a staple of pop culture. With over a 100 million units sold, it is also one of the largest selling consumer electronics products. No wonder that the market for iPod accessories is massive, and growing at a tremendous rate.

The range of iPod accessories stretches from the extremely useful (such as a set of portable speakers), to the outright stupid (an iPod accessory that holds toilet paper). Whatever your needs, there is a probably an accessory for you.

The most essential accessory is, of course, a high quality case. For whatever its worth, the iPod is still a delicate device. A tumble down a flight of stairs could easily damage the screen, making your $300 investment go to waste in a matter of seconds. A quality case will help to protect your player from damage as well as dust.

Voice over Internet Protocol , also called VoIP or Internet telephony, is the transportation of voice conversations over the internet or through any other IP-based network rather than the public switched telephone network (PSTN).

Protocols which are used to carry voice signals over the IP network are commonly referred to as Voice over IP or VoIP protocols. Some cost savings are due to utilizing a single network to carry voice and data. Users that have existing underutilized network capacity can use VoIP at no additional cost. VoIP to VoIP phone calls on any provider are typically free, while VoIP to PSTN calls generally costs the VoIP user.

There are two types of PSTN to VoIP services: DID (Direct Inward Dialing) and access numbers. DID connects 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. One can also find DID that are free to the VoIP user but charge the caller instead.

Key features of VoIP:
VoIP can facilitate tasks that may be more difficult to achieve using traditional networks, such as:
• Routing phone calls over existing data networks to avoid the need for separate voice and data networks.
• Incoming phone calls can be automatically routed to your VoIP phone, regardless of where you are connected to the network. Take your VoIP phone with you on a trip, and receive incoming calls whenever you are connected to the Internet.
• Free phone numbers for use with VoIP are available in the USA, UK and other countries from several organizations.
• Call center agents using VoIP phones can work from anywhere with a sufficiently fast and stable Internet connection.
• Many VoIP packages include PSTN features that most Telcos normally charge extra for, or may be unavailable from your local Telco, such as 3-way calling, call forwarding, automatic redial, and caller ID.
• VoIP allows users to travel anywhere in the world and still make and receive phone calls.