SIP or Gulp

In simple terms, SIP provides a virtual telephone line over a network connection (either a private network or the Internet). As advancements in technology and phone systems continue to develop, the use of SIP instead of traditional communication methods is becoming more and more common.

SIP brings about a number of advantages for business, including the below:

Easy Porting of Numbers

Looking to move premises? When moving from one place to another, it’s not always possible to take you current telephone numbers with you. When using SIP Trunks, this isn’t the case. It’s very easy for business to take their telephone numbers with them, irrespective of where they’re moving to as number are not tied to specific telephone exchanges or locations.

Non-geographic numbering

Telephone numbers are no longer fixed to a geographical location. This assists smaller businesses to portray themselves as much larger with a national presence, and provide local numbers where there is a high density of customers/prospects or in cases where a geographically focussed market campaign is to be run.

Lower implementation and call costs

Generally SIP trunks are available at a lower cost than ISDN services, with call rates usually being more competitive than as well. This reduces the cost of implementing and running a telephone system. In addition, in multi-site networks utilising the same SIP provider calls between sites are generally free-of-charge.

Quicker provisioning

Call Flow can generally install new or extra lines in a shorter time frame than ISDN lines. As the commissioning of trunk lines is generally the critical factor for the overall new system “go-live” for a new system, this reduces the initial time for implementation of a new system. This also allows new trunk lines to be provisioned quickly and easily for short-term projects and temporary offices.


SIP trunks can often be scaled on a per channel basis – up or down. This allows businesses to increase or decrease the number of lines they use to meet their changing requirements, with most providers requiring a month’s notice or less to do so.

Business Continuity

Providing a mix of SIP and ISDN for our customers’ allows one trunk type to back-up the other. This ensures that if there is a problem with one service, telephone calls will still be able to get through. In addition, SIP Trunks make it very easy to move calls to another site with an appropriate IP connection and instantly resume normal service, without the need to provision new network services.