Introduction to audio Acoustics, speakers and audio terminology OCTOBER

24 Jul 2018

Axis offers intelligent security solutions that enable a smarter, safer world. As the market leaderin network video, Axis is driving the industry by continually launching innovative networkproducts based on an open platform - delivering high value to customers through a globalpartner network. Axis has long-term relationships with partners and provides them withknowledge and ground-breaking network products in existing and new markets.

Introducing SIP

Session Initiation Protocol (SIP) is used to initiate, maintain and terminate multimedia sessions between different parties. Usually these sessions consist of audio, but sometimes they consist of video. SIP is the standard protocol used in Voice over IP (VoIP) applications and unified communication platforms. SIP is for example supported by AXIS C3003-E Network Horn Speaker and AXIS A8004-VE Network Video Door Station and constitute a new way to connect, integrate and control your Axis network products.

How does it work?

In order to communicate using SIP at least two SIP clients are needed. A SIP client can be a SIP hardphone, softphone, mobile client or SIP enabled Axis product.

Each SIP client is assigned its own SIP address. A SIP address looks like an email address with a “sip:” prefix, for example, sip:bob@biloxi.ex.com [sip:@]. This identifier can be used across a number of devices and is analogous to the use of a telephone number linked to a SIM card that can be used in a number of devices.

Peer-to-peer setup – the simple way

A SIP system can take many forms. In its simplest form, the system consists of two or more SIP User Agents (UA) communicating directly with each other. This can be called a peer-to-peer setup, a direct call setup or local setup. A typical SIP address in this case would look like sip:, for example, sip:192.168.0.90

In order to make a peer-to-peer call from one UA to another on a local network all that is needed is the SIP address containing the unit’s IP address. Note that not all SIP clients support peer-to-peer calls.

Using a SIP server (PBX) – adding more possibilities

A SIP-based VoIP infrastructure scales very well. The next step up in size is to use a registrar, Private Branch Exchange (PBX) or SIP server, as a central hub. The SIP UAs register with the registrar and can then reach each other’s SIP UAs simply by dialling an extension on the PBX. A typical SIP address in this case would look like sip:@ or sip:@ such as sip:6007@ mysipserver.net. A PBX works like a traditional switchboard, showing the clients’ current status, allowing call transfers, voicemail, redirections and much more.

A SIP server usually includes proxy, registrar and redirect functionality. Proxies route calls and provide additional logic to incoming calls. Registrars accept register requests and act as a location service for the domain that it handles. Redirect servers redirect the client to contact an alternative SIP address.

The SIP server can be set up as a local entity or it can be located offsite. It can be hosted on an intranet or it can be hosted by a third party provider. When making SIP calls across sites, calls are normally initially routed through a set of SIP proxies. These proxies query the location of the SIP address to be reached.

In order to use your device with a SIP server you need to create an account on the server with a specified user ID and password. To register your device to the server, you need to set up an account on the device entering the server address, user ID and password.

Using SIP trunks – assigning a telephone number

Using a SIP trunk, SIP UAs can even be switched to the traditional analog telephone network (PSTN). This way you can assign a traditional telephone number to the SIP UA.

When used with a SIP trunk the device connects to the server in the way described above. The service provider will usually charge extra for external numbers.

Contd...

Download PDF

1 Capability Green
LU1 3LU
Luton, Bedfordshire
United Kingdom

Purr of approval as Axis helps safeguard future of small business
Product News

Purr of approval as Axis helps safeguard future of small business

“ Being able to view the footage on our phones in real time and flick between the different cameras in the café is great. We can zoom in on different areas and slow down or speed up the playback.” Jaya Da Costa, Owner of the Pause Cat Café.

Read more

Axis cameras selected for IP video upgrade at Canary Wharf Station
Product News

Axis cameras selected for IP video upgrade at Canary Wharf Station

“The Axis cameras have proved exactly the right fit for London Underground here at Canary Wharf station. As we move to 24-hour operation on London Underground stations in a few months’ time, reliability and ease of maintenance are all key operational requirements. Axis cameras have met all these needs and I anticipate they will be deployed in other Jubilee Line extension stations as they are upgraded over the next few years.” Dave Perry, Delivery Manager, Station Capital Expenditure, London Underground.

Read more

List your business for free

Create a business listing on the UK's leading security and fire directory

Get the IFSEC Global newsletter

The latest security and fire news, trends and insights