With VoIP, technological innovation is changing the way we communicate. This time it is coming in the form of changing the way telephone calls are transmitted. It brings with it several new capabilities that change the meaning of the phrase telephone call through the use of Voice over Internet Protocol (VoIP). Basically, VoIP means voice transmitted over a packet data network. VoIP is often referred to as IP Telephony because it uses the IP protocols to make possible enhanced voice communications throughout the world, wherever IP connections have been delivered. IP Telephony unites a company's many locations, including mobile workers, into a single converged communications network. Telephony calls using VoIP go above and beyond what's been possible in the past. When it comes to placing telephone calls, VoIP provides a range of support services and features unequalled in the world of telephony, but above all deliver them at low cost.
How Does VoIP Work?
Voice over Internet Protocol means basically what the acronym states: Voice travels over an Internet Protocol. Internet Protocol refers to the type of rules that the network uses to send and receive signals. IP Telephony works by converting voice communications into data packets. Conveniently, it runs on the popular Ethernet LAN (local area network) technology, which currently supports over 96 percent of the worlds companies' LANs
.Circuit-switched or Time-Division Multiplexed Telephony
Before digital networking with the Internet took off, everyone had to use the "Plain Old Telephone Services" (POTS). These run over a network called the Public Switched Telephone Network (PSTN). The PSTN has been around since the telephone was invented in either analog or digital form using circuit switched technology where the telephone call gets exclusive bi-directional use of a wire - or circuit - while the call is in progress. Because the circuit is exclusive to each conversation, PSTN and private branch exchanges (PBXs) must be sized to cope with peak demand and have enough circuits available for all expected conversations. This is not a flexible approach and results in a lot of infrastructure investment that the telephone companies need to recoup, via the cost of access charges and calls. The Internet has changed this - where data services have driven down access charges and allowed voice to "travel for free" over a multipurpose data network.
Packet-Switched Telephony
Unlike circuit-switched connections, which always require use of dedicated bi-directional circuit for the duration of a call, VoIP technology has enabled telephony and other new and novel features and services to run over fixed and wireless networks including private local area networks. These newer network types use packet-switched protocols. Packet-switched VoIP puts voice signals into packets. Along with the voice signals, VoIP packets include both the sender's and receiver's network addresses. VoIP packets can traverse any VoIP-compatible network. Along the way, they can choose alternate, shared paths because the destination address is included in the packet. The routing of the packets is not dependent on any particular network route which means the network provides can provide a reliable service at a fraction of the cost of circuit switched providers.
What Advantage Does IP Office Have?
IP Office can provide support of PSTN, POTs, digital time division multiplexed phones AND digital IP phones all on the same system. This means you don't have to abandon the past to embrace the future, IP Office allows all the technologies to co-exist. IP Office connects to the PSTN and to IP trunks (the VoIP equivalent) so providing a "Hybrid" PBX function - where both legacy and future technologies can be used together to minimize operating costs and offer optimize business communications through both voice and data.
IP Office has digital telephones built on both TDM and IP technology that provide the same user interface offering a flexible choice of solution that can mix, for example TDM phones in the office and IP phones at a remote site of at home. With the choice of IP phones including real and virtual (software) phones, IP Office can take communications to a new level.
Buying IP Office allows you choice - you can use the pure POTs or the pure VoIP capabilities of IP Office, or use both at the same time to allow seamless technology transition of your business without the disruption of having to choose between them now.
IP Office Turns VoIP into IP Telephony
In order to make use of VoIP, IP Office uses signaling protocols called H.323 right now, and Session Initiation Protocol (SIP) which allow IP Office to establish end-to-end connections for the voice path through the IP network. It ensures each end of the connection is able to transmit and receive voice and provides the network addressing for end to end packet transmission. IP Office also allows for connecting between the different technologies by translating the signals they use, for example an analog phone may wish to connect to a VoIP destination. This requires both the signaling and voice transmission to be translated - IP Office does this easily as it contains technology elements called gateways and gatekeepers that enable translations to happen.
With a conventional telephone system you plug your analog or digital TDM telephone into an extension socket connected to your PBX or Key System. With IP Telephony you connect your digital IP telephone to your IP PBX via the LAN. There are two basic types of IP phones:
- A physical phone, which looks very similar to a standard telephone (IP Hard Phone)
- A software application (Phone Manager PC Softphone) which runs on the user's PC, allowing them to use either a headset/microphone to make/receive calls anywhere they have IP connection
IP telephony has the advantage of allowing extensions to be deployed both locally and remotely through the use of IP routing and IP VPN services.
When making use of IP telephony, there are a number of data centric considerations such as which data types have priority on the IP network when there is contention. This is set with IP/TCP "quality of service" and should not be ignored. In situations where LAN Bandwidth is limited, a quality of service capable LAN switch should be used to ensure voice packets are transmitted with the required priority on the network. If not, the conversation carried over IP appears as broken up (due to packet loss) or has unacceptable delays introduced in the conversation (latency & jitter).
IP Office VoIP Telephony Features
Gatekeeper
The IP Office gatekeeper allows the registration of up to 16 IP extensions on the Small Office Edition, 190 IP extensions on the IP406, 360 IP extensions on the IP412 and 272 IP extensions on the IP500, less the number of analog and digital TDM telephones already configured on the system
.Gateway
The Voice Compression Module provides the H.323 gateway function that allows IP extensions to make calls to other non-IP devices. The maximum number of simultaneous calls is limited by the number of channels available on the Voice Compression Module. IP Office must be fitted with an optional Voice Compression Module to enable IP telephony.
Silence Suppression
Silence suppression is a technique used to make the best use of available bandwidth, such as the connection over which the caller is listening, not speaking. Silence suppression works by sending descriptions of the background noise, rather than the actual noise itself, during gaps in conversation thereby reducing the number and frequency of voice packets sent on the network. Background noise is very important during a telephone call. Without noise the call will feel very unnatural and give a perception of poor quality.
Compression
IP Office supports a wide range of voice compression standards including G.711, G.729a and G.723.1. The method of compression can be either automatically established on a call-by-call basis or be configured on an individual extension basis.
Fast Start
When fast start is supported by an IP extension, this facility reduces the protocol overhead allowing an audio path to be established more quickly.
Out of Band DTMF
When out of Band DTMF is configured on an IP extension, the extension will signal to the other end of the connection which digits need to be regenerated by a local DTMF generator on behalf of the sending IP extension. This is useful when navigating external voicemail systems and Auto-Attendants.
Direct Media Path
Direct Media Path allows the speech path between two IP extensions (after call setup) to be routed directly to each other. This allows the IP Office system to free up voice compression resources after establishing the end to end connection, allowing the resources to be used in the most efficient way.
Auto-Create Extensions
IP Office can automatically create an extension entry for new IP phones added onto the local area network. In cases where the local area network is not secure this facility can be disabled, but simplifies installation of IP telephone systems
Fax Transport
Fax Transport allows fax calls to be routed over VoIP trunks between IP Office systems on an IP network using a proprietary IP Office transport protocol. This is different from the T.38 protocol which is not supported.
Avaya IP Office Phone System Features List
New! Have you seen our new Avaya IP Office Phone System site at http://officephonesystem.co.uk? Every IP Office Phone System feature has been updated there, and it also includes all the latest information about Avaya IP Office Release 9, out September 2013.
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Telefonix Voice & Data,
437 London Road, Camberley
Surrey, GU153HZ, England
Tel: +44 01252 333 888
Company Reg: 04351046