SIP (Session Initiation Protocol)

How do I view Neil Howard Telecoms' SIP Products?

To view Neil Howard Telecoms' SIP products please CLICK HERE.

What is SIP?

SIP is the next logical step in the evolution of voice communications; routing voice calls over the internet provides additional features over and above ISDN and analogue lines. They are more cost effective.

SIP or Session Initiation Protocol is split in to three different yet over lapping technologies; Voice, Text and Video. The 3G mobile network is built on SIP protocols. You may have heard of presence, as in best method of contacting some one, either by voice, text or e-mail, this is also based on SIP, this is an enterprise application which will rapidly move into the SME market. Companies such as Microsoft have been actively using SIP as a protocol for a range of applications such as unified communications server.

What are the benefits of SIP?

SIP trunks will dramatically reduce your calling costs by routing your calls over an IP network as opposed to the traditional public telephone network which uses analog or ISDN lines. There are also several other advantages to SIP. For example, your telephone numbers moves when you do, and you can answer a London call in Belfast.

The Voice World

SIP provides a signalling and call setup protocol for IP-based communications that can support a superset of the call processing functions and features present in the public switched telephone network (PSTN). SIP by itself does not define these features; rather, its focus is call-setup and signalling. However, SIP has been designed to enable the building of such features in network elements known as Proxy Servers and User Agents. These are features that permit familiar telephone-like operations: dialling a number, causing a phone to ring, hearing ring back tones or a busy signal. Implementation and terminology are different in the SIP world but to the end-user, the behaviour is similar.

What is a SIP trunk?

A SIP Trunk is the equivalent of an ISDN channel, depending on your telephony equipment you can mix and match the amount of SIP Trunks and telephone numbers/DDI ranges

What level of voice quality can I expect using SIP?

With the correct configuration you can expect quality equivalent to that of an ISDN line when using SIP.

How reliable is SIP?

VoiceFlex, Neil Howard Telecoms Partner, itself is highly reliable. At the time of publication, we have had no interruptions to service since our first server went live more than a year ago. The only threats to availability are in the network connection between your premises and our data center. SIP service has a reliability comparable with traditional phone lines

Are emergency services supported by SIP?

No, emergency service are not supported by SIP. It is essential that you have at least one analog line for emergency services. This can be the line over which your ADSL connection is hosted.

Why Neil Howard Telecoms and not another SIP provider?

While there are many SIP providers in the UK, we lead the way for business customers with PBXs using multiple trunks. We have tested extensively with PBX manufacturers and can provide a smooth transition from ISDN to SIP.

What do I need to get started?

You need a SIP enabled device (PBX or handset) and a broadband internet connection, such as ADSL. We recommend the use of our VxDSL broadband product, which includes both the connection and the router.

Can we keep our old number(s) with SIP?

Yes, old number can be ported so that you can receive incoming calls via SIP.

What telephone number will we be given?

New numbers can be ordered. You can select which area code you would like, so that you can have a local number.

Is fax supported with SIP?

No, fax is not currently supported over SIP. Fax over SIP is a very new technology. We are monitoring developments and plan to add this feature to our SIP service in the future.

What codecs are supported with SIP?

By default we support the high quality G.711 codec using μ-law or A-law. We can also enable G.729 on request. Please contact us if would like G.729 enabled.

How can I make SIP troubleshooting easier by taking a network trace?

If you are having trouble connecting, or experiencing bad call quality, you can accelerate your support request by supplying our SIP support team with a network trace. This should only be attempted by users with technical knowledge. It can be done with the free Wireshark program. Install the software on the computer on which your SIP PBX server or SIP soft-phone is installed, or alternatively on a computer which shares a hub with your PBX. Read the user-manual and familiarize yourself with the privacy implications before using this software. Run a trace on port 5060 (connections problems) or all ports (quality problems) while attempting a call. Save the trace in PCAP format and attach this to an email to the support team.

Do you have any further questions regarding SIP?

Please contact Neil Howard Telecoms Customer Support on 08702 646464.