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SIP Trunking: Overview


Moving from PSTN to SIP trunking

When you’ve decided you’re going ahead with your migration to SIP, you need to know what happens next. The process from deciding to move to rollout must be planned meticulously. There are a few key areas to take care of.


To get a jump start on your SIP migration, you can help your service provider by gathering your number information. The longest part of your SIP migration is the number porting process.

Whilst the industry dictates a set period to allow both parties to agree a date, there are often delays when validating your numbers. These delays are usually down to historic changes in address or when number ranges have been added over time. Businesses typically use specific numbers per department so planning for numbers to be coordinated is crucial.

Communications Plan

Changing business communications will impact your users. This means you need to keep them informed. The likelihood of issues and tickets raised is dramatically reduced when everyone is well informed.

Users do not need to know every fine detail of the migration. However, a regular update of works happening will benefit everybody involved in the process.


During the period when number porting is planned, your provider should setup a test scenario for your IT and PBX team to run through common calling scenarios.

It is important to conduct thorough SIP testing to ensure every possible situation has passed its criteria. Only then should you give the green light to proceed with migrating to SIP in real time.


On your go live date, numbers will be scheduled to start moving from one network to another. During this phase, equipment can be moved over from your existing ISDN or PSTN phone lines and connected to your SIP equipment.

Making your users aware of this key date and time is the must crucial element to include in your communications plan.