Traditionally, telephone systems have been connected to the outside world via standing PSTN telephone lines or via an ISDN service, typically ISDN2 or ISDN30. However this traditional picture has been changing for some time. With the true emergence of VoIP there is now an increased uptake of SIP (Session Internet Protocol) Trunking – and with good reason.

SIP Trunks allow a business to replace expensive traditional fixed lines with an internet-based SIP Trunking service. This means reduced fixed line costs and, in addition, reduced call tariffs.

Most modern PBX systems support SIP ‘out of the box’ and PBX systems pre-2007/8 can function with SIP Trunks (requiring an additional SIP-ISDN Gateway conversion device).

Why does a business need SIP trunking?

If your business currently uses ISDN2 or ISDN30 circuits, has a high call spend or has internet connectivity through a leased line or dedicated SDSL service, then it is certainly worth considering SIP Trunking as a replacement. SIP Trunks can offer a significant cost savings by:

• Only paying for the capacity a business needs. ISDN2 provides 2 channels capacity. ISDN30 allows a minimum of 8 channels and a maximum of 30. Should a business require, say, 31 channels then the business would need to rent two ISDN30 services: one with a capacity of 30 channels and the second with a capacity of 8 – therefore paying for 7 additional channels that the business does not necessarily require. SIP Trunking, on the other hand, allows single channel increments with the maximum number of channels is only dictated by bandwidth.
• Eliminating the need for ISDN lines and therefore rental charges. SIP Trunking replaces the need for ISDN lines, instead requiring more cost effective internet connectivity.
• Cheaper rental charges. In recent years, internet connectivity charges have dramatically reduced and continue to fall in a competitive market. Within the same time-frame this is has not been true of ISDN rental charges.
• Cheaper call charges. SIP Trunk calls are nearly always cheaper than ISDN calls, even with reputable least cost routing in place. Compared to BT Standard Business rates, it is not uncommon for calls to be between 40%-90% cheaper.
• Less hardware costs. Traditionally, additional ISDN channels have meant the need for additional cards for the PBX. As well as the cost of the extra card there is an associated license fee, installation cost and annual maintenance charges (which are typically based upon a percentage of the overall equipment list price). SIP Trunks do not require any further hardware.
• Increased resilience with built-in disaster recovery. Although a robust business grade internet service should be every bit as reliable as traditional telephone lines, having the ability to route calls over alternative paths is provided by reputable SIP Trunk providers with automatic mobile phone inbound call failover.
• Increased connectivity capacity. In the past, businesses have rented the number of ISDN lines depending on how many concurrent calls they expect to make during a peak time. SIP Trunks allow a data type network to carry voice calls. Often by combining voice and data networks (ensuring that QoS is in place such that voice has priority over data) businesses are able to increase the number of potential concurrent calls.

Should your business be without SIP Trunking?

Still not sure? Some businesses start with a hybrid solution: this means continuing to place incoming calls on the existing traditional ISDN lines whilst concurrently reducing, but not eliminating, the number of ISDN channels. This removes the need to port the telephone numbers from ISDN to SIP at this stage and all outgoing calls can be routed through the new SIP Trunk. This then gives immediate line and call charge savings. Though this model does not remove all ISDN rental charges it is a quick and simple way to test and have confidence in SIP Trunks.

How do I get a SIP trunk for my business?

Changing to a SIP Trunk service is a straightforward task: if your existing data network has the capacity to carry calls and can offer QoS then it could be used, otherwise we can provide a range of delivery networks ranging from high quality business grade dual DSL services to leased lines. As we also offer SIP Trunking and telephony services, we act as a single port of call.

Please call us on 0845 0000 500, or alternatively fill in our Contact Form. We can discuss your options and potentially activate a SIP Trunk service within days so that your business can benefit from reduced costs as soon as possible.

This entry was posted on Thursday, October 29th, 2009 at 10:22 am and is filed under Latest News, SIP. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

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