Voice Migration. The switch to modern telephony that works.
Many organisations know their phone system is no longer fit for purpose. But the thought of a migration causes concern. What happens to the phone numbers? What if something becomes unreachable during the switch? And who actually knows the old system well enough to migrate it safely? We hear these questions in every migration project. And we have the answers. weSystems accompanies organisations in a structured way from the first conversation through analysis and planning to go-live and ongoing operations afterwards. From ISDN, 3CX, Cisco and classic PBX systems to Microsoft Teams, SIP Trunking or another modern platform.
Those who wait end up migrating anyway. Just under more pressure.
ISDN has been switched off. Older PBX systems are no longer receiving updates. Vendors like Mitel and Unify have changed their roadmaps. And anyone who experienced the VMware situation after the Broadcom acquisition knows what happens when you wait too long before a switch becomes unavoidable.
A voice migration is not a project that goes well under time pressure. It needs a careful analysis of existing infrastructure, realistic planning with buffers, structured testing and a controlled cutover that your users barely notice. Those who plan now can do all of this calmly. Those who wait will still do it eventually, just under pressure.
We migrate organisations from classic PBX systems, 3CX, Cisco CUCM, Avaya, Unify and ISDN to modern platforms such as Microsoft Teams with Direct Routing or Operator Connect, to SIP Trunking with weSystems as carrier, or to hybrid scenarios where some users are already on the new platform while others are still on the old system.
How a voice migration works at weSystems.
Every migration is different. But the process that leads to a controlled and disruption-free switch always follows the same phases.
Analysis and inventory
We capture your existing telephony completely. Which systems are in use, which phone numbers and number blocks exist, how are call queues and forwarding configured, which carrier contracts are in place. Only when we have the complete picture does planning begin.
Target architecture and migration concept
Based on the analysis we develop the target architecture and an individual migration concept. Which platform fits your requirements, how is number porting organised, which locations migrate in which sequence and what fallback scenarios exist.
Technical preparation and configuration
We set up the target platform. SBC configuration, SIP trunk connection, dial plans, voice routing policies, call queues, auto attendants, hunt groups. Everything is built in a test environment and fully tested before it goes into production.
Pilot operations and user acceptance
A selected group of users or a first location goes onto the new platform. We test voice quality, reachability, emergency calls and all configured scenarios under real conditions. Only when the pilot runs smoothly does the rollout extend to all locations.
Location rollout and cutover
Location by location is migrated. Number portings are coordinated, cutovers take place outside core business hours and every location receives documented sign-off. Parallel operation of both systems during the transition phase is standard, not an extra.
Go live, sign-off and ongoing operations
After go-live we stay actively involved during the first weeks to address any questions quickly. The infrastructure then transitions to ongoing operations with 24/7 support, monitoring and a dedicated contact who knows your environment.
Systems we migrate every day.
ISDN und classic PBX systems
Siemens HiPath, Mitel, Unify OpenScape, Alcatel-Lucent, Panasonic
3CX
Migration to Microsoft Teams Direct Routing or Operator Connect, including transfer of existing phone numbers and configurations
Cisco
Cisco CUCM, Cisco UCM Cloud, Webex Calling – migration to Microsoft Teams or SIP Trunking, including gateway replacement and endpoint migration
Avaya
Avaya Aura, IP Office – migration to Microsoft Teams or cloud telephony, including number porting and endpoint concept
Microsoft Teams to Teams
Migration from Teams Free Calling to Direct Routing or Operator Connect, merging multiple tenants, international expansion of existing Teams environments
What you genuinely experience differently after migration.
Your phone numbers stay
Existing phone numbers are fully ported. Your customers and partners notice nothing about the switch. We handle coordination with releasing carriers.
No outage during migration
Parallel operation of both systems is standard, not an extra. We only switch over when everything has been tested and the cutover takes place outside core business hours.
One platform for all locations
Instead of local PBX systems at every location, a central voice platform that works the same everywhere and is managed centrally. That saves operating costs and significantly reduces complexity.
Microsoft Teams as a complete phone system
Call queues, auto attendants, hunt groups, call recording, voicemail and conferencing, all natively in Teams, without a separate phone system and without a second interface.
Lower ongoing costs
Elimination of maintenance contracts for old PBX systems, consolidation of carrier contracts, lower call charges through SIP Trunking. The saving is measurable.
Future-proof infrastructure
Modern cloud telephony grows with your organisation. New locations, new users, new requirements can all be accommodated without hardware investment.
What customers say who have already taken this path with weSystems.
DB Schenker operates a global voice platform and has created a central solution for all national subsidiaries. Telephony is a central element in communication with our business partners and is business-critical for us as a globally operating logistics company. From project management through consulting to technical support, we have been and continue to be very successfully supported by our partner weSystems. We look forward to continuing our good and collaborative partnership.
Kuno Pfeiffer, Service Manager, Schenker AG
Migrations succeed when the team behind them knows what it is doing.
A voice migration is not a project where you can hope for it to work first time. Number portings that happen at the wrong moment. Dial plans that do not cover every scenario. Locations that were not tested in time. Emergency calls that are not routed with accurate location identification after cutover. We know these problems because we have seen them in practice and resolved them.
Our team combines telephony expertise with structured project management. We understand how classic PBX systems are built, how carrier portings work and what Microsoft Teams requires technically. That allows us to plan migration projects realistically, identify risks early and prepare cutovers so they run smoothly.
And because we also operate the platform after migration, we already think about operations during the design phase. What is configured well causes no problems in everyday use.
Related Services
Direct Routing for Micrsoft Teams
You are migrating to Microsoft Teams and want to integrate telephony via Direct Routing? We configure and operate the SBC infrastructure, dial plans and voice routing policies.
Global SIP Trunking
After migration you need a reliable carrier with global reach? We provide SIP Trunks in over 55 countries with own SBC infrastructure in EMEA, USA and APAC.
Cloud SBC Management
We operate AudioCodes Session Border Controllers after migration as a managed service, including OVOC monitoring, firmware management and 24/7 support.
Frequently asked questions
What is voice migration?
Voice migration describes the structured transition from classic phone systems to modern IP-based or cloud-based communication systems. This includes migration from ISDN, 3CX, Cisco, Avaya and other systems to platforms such as Microsoft Teams, SIP Trunking or hybrid cloud solutions.
Which systems can weSystems migrate from?
We migrate from classic PBX systems (Siemens HiPath, Mitel, Unify, Alcatel), ISDN, 3CX, Cisco CUCM, Avaya Aura and IP Office, as well as from older Microsoft Teams configurations to modern target platforms.
Which platforms does weSystems migrate to?
We migrate to Microsoft Teams with Direct Routing or Operator Connect, to SIP Trunking with weSystems as carrier and to hybrid scenarios. The target platform is agreed together based on your requirements, your existing infrastructure and your budget.
Does migrating the phone system involve outages?
Not with us. Parallel operation of both systems is standard, not an extra. We only switch over when everything has been tested and carry out cutovers outside core business hours. Every location receives documented sign-off before the old system is decommissioned.
Are existing phone numbers retained during voice migration?
Yes. Existing phone numbers and number blocks are fully ported. We coordinate porting with releasing carriers, configure the SIP trunks and carry out technical tests and cutover together with you.
How does a professional voice migration work at weSystems?
In six phases: analysis and inventory, target architecture and migration concept, technical preparation and configuration, pilot operations, location rollout and cutover, and go-live and ongoing operations. Every phase is documented and signed off together with you.
How long does a voice migration take?
That depends on complexity, the number of locations and number portings. Simple migrations are completed within a few weeks, complex international projects like that of DB Schenker take several months. We plan realistically and communicate transparently.
What does a voice migration cost?
Costs depend on scope, complexity, number of locations and the target platform. After an initial conversation we put together a transparent, individual proposal for you without hidden charges.
Does weSystems also support 3CX migration to Microsoft Teams?
Yes. We migrate 3CX environments to Microsoft Teams Direct Routing or Operator Connect, including transfer of existing phone numbers, configuration of call queues and hunt groups, and user training.
What support do organisations receive after migration?
We stay by your side after project completion with 24/7 support, monitoring, individual SLAs and dedicated contacts who know your system because they built it themselves.