--- title: Certified SIP Trunk | Works With Your Current IP-PBX description: Compatible with any phone system on the market, certified by Yeastar, Swyx, STARFACE, and others. Request a free technical diagnostic. --- [![Virtual-Call Ihr Telekommunikationsanbieter](https://www.virtual-call.net/hs-fs/hubfs/VC%20Logo/New/vcall_logo_753x226.jpg?width=300&height=90&name=vcall_logo_753x226.jpg "Virtual-Call Ihr Telekommunikationsanbieter")](https://www.virtual-call.com) # Your headquarters is in one country. Your offices are in several. Your telephony should be one.   #### One provider, one contract, one invoice, and one technical contact for your entire international operation with local numbers in over 60 countries and integration with the phone system you already use.   [Request a Free SIP Trunk Diagnostic](https://share.hsforms.com/1N3znDKd0QGyumCG_v_fJiQ46tu8) ## How many telephony providers is your company managing right now? If the answer is more than one, you already know the hidden cost: contracts with different terms and renewal dates in every country; invoices arriving in different currencies on different cycles; and support tickets that have to be raised in three languages, each with its own SLA.  This rarely shows up on the cost sheet. It shows up when a branch office loses its lines on a Friday evening, and no one knows who to escalate to. **Transition:** That is precisely the scenario Virtual-Call's SIP Trunk removes.    ## One provider for the headquarters and every branch office Virtual-Call is an international communications operator, not a reseller. That means the connection between your headquarters and each office abroad runs through a single interconnection under a single contract with local termination in each country, not international calls in disguise. **Three pillars:** ### **1. One contract, one invoice** Consolidate telephony across all locations into a single commercial relationship. No renegotiating terms country by country. ### **2. Support from a single point** Multilingual 24/7 technical support with one escalation path for the entire operation, regardless of where the issue occurred. ### **3. Local presence where you operate** Fixed numbers in over 60 countries with guaranteed caller ID (CLI). Your customer abroad sees a local number, not an international one. [Request a Free SIP Trunk Diagnostic](https://share.hsforms.com/1N3znDKd0QGyumCG_v_fJiQ46tu8) ## Your current phone system keeps working The main objection in any SIP Trunk project is not price; it is integration risk. That is why our service is certified with the market's leading phone system manufacturers:  - Unify-Mitel - Swyx - STARFACE - AGFEO - Yeastar Certification means compatibility tested and approved by the manufacturer itself, not just “should work.” You keep the infrastructure investment you have already made and change only the operator behind it.  ![Comparison table: Today versus With Virtual-Call. One contract for the entire operation instead of one per country, one consolidated invoice, multilingual 24/7 support with a single point of contact, minute packages per trunk, integration with your existing IP-PBX, and local termination in 60+ countries.](https://www.virtual-call.net/hs-fs/hubfs/vantagens-tabela-en.png?width=1073&height=464&name=vantagens-tabela-en.png "Comparison table: Today versus With Virtual-Call. One contract for the entire operation instead of one per country, one consolidated invoice, multilingual 24/7 support with a single point of contact, minute packages per trunk, integration with your existing IP-PBX, and local termination in 60+ countries.") Native Microsoft Teams integration, high-quality voice, and on-demand scalability: add capacity as your operation grows, without a new infrastructure project.  [Request a Free SIP Trunk Diagnostic](https://share.hsforms.com/1N3znDKd0QGyumCG_v_fJiQ46tu8) ## What our customers say *“Good connection and first-class advice. As an internationally active company based in Switzerland, we have chosen Virtual-Call as our VoIP provider. Our customers appreciate the local phone numbers and low costs. The call quality is impeccable.”*   Urs Pavoni - CEO, INTERVILLA GmbH   International communications operator since 2013, headquartered in Switzerland, serving companies across Europe, Latin America, and beyond.  ## What happens during your free diagnostic It is not a sales presentation. It is a technical assessment led by a specialist, in about 40 minutes, with three concrete outcomes:  ### **1. A map of your current operation** Which countries, how many extensions, which phone system, which contracts are active, and where cost duplication is happening. ### **2. A compatibility check** Whether your IP-PBX is certified, what needs to be configured, and how number portability and emergency calling work in each country where you operate. ### **3. A migration plan** Steps, timelines, and risk points so you know exactly what to expect before making any commitment. **Risk reduction:** At the end, the assessment is yours, even if you decide not to move forward with Virtual-Call. And if you want to see the service working in practice, we offer a free 14-day trial.   > Ready to experience the difference with Virtual-Call? Fill out the form below and start your 14-day free trial to discover how our SIP Trunk can drive your business forward! Virtual-Call GmbH, 2026.