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SIP offers voice services with increased control, at reduced cost.

SIP trunks

ISDN (the integrated services digital network) is over thirty years old now, and is due to be completely shut off by 2025. But there's an alternative, and it's one with a lot more benefits for businesses.

It's being replaced by what's called SIP trunking, a public IP telephony service based on session initiation protocol lines. DuoCall enables companies with traditional ISDN, analogue and SIP-based customer telephone systems to connect to the new public IP switched telephone networks. Start feeling the benefits straight away!

So what is SIP trunking?

SIP trunking is a public IP telephony service based on session initiation protocol lines; in other words it’s an application layer protocol that's IP-based. It’s estimated that the SIP market is worth over £150 million and is aimed to conjoin voice and data services in order to be more economically efficient for a business.

DuoCall works hard to help companies that have traditional ISDN, analogue and SIP-based telephone systems connect to the new public IP switched telephone networks. This way companies will experience the benefit of SIP trunks immediately!

There’s no need to change your number when you transfer conventional ISDN lines over to SIP trunks! We can port your telephone numbers to our next generation public switched telephone network (PSTN) voice switches.

What are the benefits of switching to SIP trunking from ISDN?

Save money!

Save money!

  • Save 50% in line rental
  • Save 25% in call charges
  • Avoid handoffs by your telecom provider
  • No need to purchase PRIs for each site
Built-in disaster recovery

Built-in disaster recovery

  • Your number is no longer tied into a dedicated circuit
  • Automated switching to secondary calling route when unavailable
  • Have calls directed to any phone you want!
  • Ensure that your number is always available
Be more flexible

Be more flexible

  • No need to change numbers
  • Avoid being tied into a telephone exchange
  • Have your number hosted in a central database and be able to pick up anywhere on or off the network!
  • Avoid unecessary call forwarding

1. Save money

Save up to 50% on your line rental costs and up to 25% in call charges when compared to traditional ISDN telephony.

Although ISDN connections do the job, internal calls are still required to traverse to the PSTN if they are to reach the target destination. This can be problematic for a business as primary rate interfaces (PRIs) need to be purchased for every site. To add to the cost of PRIs, internal calls made through ISDN channels are handled in the same way as external calls.

SIP telephony trunks are delivered over data lines that are used for internet and Wide Area Network (WAN) connections, both of which you have more than likely already got! By using the same infrastructure and combining voice as another application on these data lines, the existing dedicated analogue and ISDN2/30 lines are no longer required. Internal calls over SIP phone lines remain within the company’s WAN, therefore business’ are able avoid handoffs by their telecommunications provider; for that reason extra charges for calls traversing to the PSTN are avoided.

Using SIP trunks won’t alter the cost of external call charges because they need to be handed off to the PSTN, consequently there’s no need to purchase PRIs. This is because the IP-based SIP traffic can traverse through the company’s WAN and be handed off. Without the cost of a PRI for each individual site, SIP is cost effective in multiple ways.

DuoCall SIP Trunking across Sheffield and the UK

2. Built-in disaster recovery

Avoid having your phone number being tied into a dedicated circuit that terminates in your office.

When you use SIP trunks as your phone line, your business’ telephone number will be programmed to ring an IP address on your internal connection (endpoint) and connect to your telephone system. If a customer calls your company, your SIP system will check your availability to get to the phone. If you’reunavailable the system will automatically switch to the secondary calling route. The secondary calling rote can be anything from a mobile phone to an office in another country!

The automatic failover between multiple locations allow the calls from one site to be received from another site, where the lines aren’t as busy. SIP trunks will ensure that your number is ALWAYS available no matter where you are. 

SIP trunking is the digital replacement for traditional phone lines

3. Flexible phone lines for when your business grows

It’s almost certain that a business that uses ISDN lines will lose their telephone number if they are to move location. The reason for this is because the geographic telephone number is tied into a physical telephone exchange. Even though a business will be able forward their calls in this situation, continuously renting numbers and lines will be very expensive. Fortunately SIP trunks can help.

SIP trunking allows numbers to be hosted in a central database and therefore can be made to ring anywhere that is on or off the network! Geographic number porting prevents the unnecessary need for call forwarding in a business!

Scale up the number of channels to best suit your company's needs

ISDN phone lines are available in circuit sizes of thirty channels per bearer with each one having a minimum of twelve channels. This means that one bearer can support twelve to thirty channels. If a business wants sixty channels you will need two bearers. However, this can cause problems as the unused overhead needs to be purchased.

Introducing SIP trunking will enable the business to have as many channels as they require! These phone lines are deployed across an existing WAN meaning that channels can be added or subtracted to a business’ demand. Where ISDN lines can take weeks to increase the number of channels, companies can add SIP channels in minutes if necessary. Another advantage over ISDN is that there’s no need to pay for any unused channels.

The only limitation is bandwidth. One SIP trunk uses 100Kbps of bandwidth when being used. As long as your business has doesn’t have very poor bandwidth the SIP trunking will provide you with the best option. 

Business phone lines - SIP trunking

Video call your business' customers for free!

Your customers will be able to video call your company (providing that they have handsets that are video-enabled) when you transfer your phone lines over from ISDN to SIP trunk. SIP voice is transferred over IP meaning that video calls are made over the internet. Although you can video call over ISDN lines, the process uses up far too much bandwidth making it a pointless task, as it’s economically detrimental for a business. 

SIP trunking supplied to businesses across Sheffield, Rotherham and the UK

Guaranteed crystal clear calls

SIP trunking can be delivered over high bandwidth connections such as FTTC and EoFTTC. These connections will make sure that your business makes and receives HD voice calls to customers (providing their handsets are compatible). A high quality phone call provides a high quality service. 

The Benefits of SIP Trunking for Business (PDF, 542 KB)

The business benefits of SIP - DuoCall's Top 3

What Can I Do Next…

  • Call our friendly Sales Team with any queries or feedback on 0333 313 5000
  • Drop us an email anytime at enquiries@duocall.co.uk
  • Find out what our customers say about us in our Case Studies section

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