Q: What is Digital Phone Service?

A: Digital Phone Service is Voice over Internet Protocol, but it has come to stand for new telephony technologies that use the internet to carry telephone signals. In the simplest terms it means making telephone calls over the internet.

Q: Is Voice Quality an Issue?

A: In the early days of VoIP telephony, quality was a serious issue and early adopters needed high-speed connections and special software and hardware. Recent advances in available bandwidth and in IP telephony technology have meant that quality is only an issue for those in areas with limited bandwidth (internet connection speed). A recent study by Infotech indicates that quality and reliability of IP telephony solutions have met or exceeded expectations in 80% of cases.

Q: Why is Digital Phone Important?

A: Ditial Phone, Internet telephony and Pearl networks are all about bringing voice technologies like the telephone and data technologies like the internet together to provide greater benefits to users. Most advertising and promotion for Ditial Phone service stresses cost savings, both for consumers and users of the services and for maintenance and operations for suppliers. But in fact, the real impact of Digital Phone service will come from the convergence of voice and data in the form of new features and capabilities. A simple example is the ability to automatically forward voicemail via email. Industry analysts predict an explosion in applications and capabilities around Ditial Phone service over the next five years.

Q: How does the Service work?

A: Using digital voice (Voice over Internet Protocol), telephone calls are passed over the internet and over corporate LANs,intranets and WANs. The basic call itself is broken down into digital packets for transmission and put back together at the other end. Management of this transmission and timing for arrival of the packets and reassembly is the key to successful service. In fact, most of the issues to do with Digital Phone service quality are to do with trying to perform the transmission over internet connections without sufficient bandwidth to keep up with calls. However, compression techniques, transmission techniques and the continual increase in bandwidth are rapidly removing quality as an issue for digital voice calls and technologies. This is extremely important since voice technologies require very little latency (time lag or delay) in the communication and must be fully duplexed (both ends of the communication must operate simultaneously).

Q: What do all the terms mean - internet telephony, packet telephony, IP telephony and digital service?

Q: What equipment do I need?

A: The simplest setup is using one of the PC/MAC-based/software-based solutions Pearl PC. These use any PC or MAC

system connected to the internet over a high-bandwidth connection like DSL or cable. The PC needs to have a loudspeaker and microphone or a headset and the software then handles the calls. This software along with a Pearl account enable you to literally call anywhere in the world, anywhere you are connected to the Internet.

The next level of setup is our Ditial Phone Service designed to replace a single or multiple regular phone line. This service requires a specialized router connected to your internet connection that splits internet traffic and voice traffic and distributes it. These routers also manage the traffic load to maintain voice call

quality. You can plug a regular telephone into them. Your service automatically includes this equipment with Pearl.

Small office and small business setups may require some kind of phone system (PBX) so that each line can have an extension and calls can be switched and transferred easily. They also need to evaluate more advanced options for conference calling, automated attendants, call grouping and many other options. Typically pricing is based around number of lines and feature sets. Pearl is an expert in whether you need to purchase a phone system or can use a virtual phone system service that Pearl offers as well.

Large organizations need to evaluate hosted or purchased solutions involving routers, switches and more heavy-duty equipment. This should include an analysis of existing networks and potential network upgrades. Peal has a team focused in this area. This is the highest growth area in digital phone service. Large organization around the globe have found the service to be reliable and extremely cost affective.

Q: Are there Digital Phone service Standards to be aware of?

A: The commonest are SIP (Session Initiation Protocol) and H.323. In practical terms, most Digital service systems currently are designed to interoperate as transparently as possible with the POTS (Plain Old Telephone System) network and do so effectively. However, they do not all communicate with one another as effectively. In addition, popular PC-based software solutions like Skype are often proprietary (unlike Pearl) and can only interoperate with other VoIP systems via conversion to and from the POTS network. H.323 and H.324 are multimedia related standards designed to provide video telephony services in conjunction with voice and data. SIP has become the standard for basic voice over IP calls (Digital Phone service). There are several groups working on bringing these standards together and in practical terms your choices are to go with a proprietary solution like Skype or to go with a standard-based SIP solution (Pearl).

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