Finland: SIP providers and connecting a number to the PBX

This page continues the general guide to connecting a provider's number to the PBX: that page covers what is the same for every carrier — the two trunk modes, what to ask the provider, what to enter in the form, network requirements and how to test the link. Here is the Finnish part: who sells a number with a SIP trunk in the country, what that carrier issues and what of it goes into Telephony → "Trunks and connections" → "Add provider".

The data was collected on 9 September 2026 from carrier websites and documents of the regulator Traficom; the links are in "Sources".

In short#

• You can buy a Finnish number with a SIP trunk, and your venue needs no licence of its own. In the eyes of the law the operator is whoever sells you the channel and the number: they file a telecommunications activity notification with the regulator and hold the right to use the numbering. You are their subscriber.
• The country's defining feature is legal, not technical: a Finnish number may not be presented as the calling party's number from abroad. The regulator forbids it outright and requires carriers to block calls arriving from the international interconnect with a Finnish number in the CallerID. Our PBX runs in a cloud outside Finland, so outbound calls with a Finnish number must be released by a Finnish carrier — the "buy a +358 from an international aggregator and call Finns from it" scheme does not survive the network. Inbound calls are unaffected, details below.
• No Finnish carrier publishes SIP trunk parameters. Neither Elisa, Telia, DNA nor Line Carrier discloses a host, a port or an authorisation method — everything is issued during the connection project. Planning to "look it up in the documentation" will not work here: the working tool is the rajapintakuvaus, the written interface description the carrier is required by the regulator to have. Demand it before signing.
• The only carrier in the country with published terms is JNT (Ostrobothnia): a package of 10 numbers and 10 channels "from 35 euros a month plus a 100-euro connection fee", and a requirement for "an internet connection with a static IP address" — exactly our model. The second candidate is Line Carrier, a carrier-independent seller of trunks aimed precisely at third-party fixed PBXs.
• Check the transport before you sign. Our PBX speaks SIP over UDP and TCP only; there is no encrypted transport on trunks. Elisa states that for cloud services "voice is delivered over an encrypted protocol" — if the interface turns out to be TLS/SRTP only, the link will not come up, see the section.
• Finnish numbers vary in length, and the PBX matches a line by the last seven digits. Two mobile numbers collide easily: 040 123 4567 and 050 123 4567 produce the same seven-digit tail and merge into one line — check this when adding a second line.
• Either way a trunk only works on a dedicated PBX with a static IP — the two trunk modes are explained in the overview.

Numbers in Finland#

The number you type on the "Lines" tab is best written in the international form +358…: at the interconnect between carriers the number is carried in exactly that form, and it will most likely arrive on the trunk the same way. The exact format of the incoming number is one of the seven questions in What to ask the provider.

⚠️ A line is matched by the last seven digits. For a Helsinki landline (9 XXX XXXX) that is practically the whole number and collisions do not happen. Mobile numbers, however, are longer than seven digits: 040 123 4567 and 050 123 4567 differ only at the start, the tail is identical, and the second such number will land on the same line. Add mobile DIDs one at a time and make a test call after each — Add the number and routing.

Who sells a number with a SIP trunk#

One important note about this list. Nobody publishes full parameters: even in the cards below, the "What to enter in the admin panel" table gives not a ready value but where that value comes from and what to clarify with the account manager. The list of questions is in What to ask the provider; four of them are critical in Finland — transport (is it TLS-only?), codecs, the authorisation method and the format of the incoming number.

JNT — SIP-trunk vaihdeliittymä#

A regional carrier in Ostrobothnia (Jakobstad/Pietarsaari, Vaasa, Kokkola) and the only one in the country that publishes trunk terms. The Basic package is "10 numbers and 10 voice channels", "prices from 35 euros a month plus a 100-euro connection fee"; Advanced is 30 channels, price on request. The service supports "most IP PBXs", direct dial-in (DDI) and calls to emergency and public services.

The sentence that matters for us is in the service description: "you only need an internet connection with a static IP address, and we can arrange one if needed; delivery goes over a VPN, a dedicated internet connection or the public network". In other words, delivering the trunk over the ordinary internet to our static address is a standard option, not an exception.

What to enter in the admin panel (Telephony → "Trunks and connections" → "Add provider" → the "SIP trunk (custom provider)" card):

What to set up with the provider: ① order the Basic or Advanced package and the number of channels you need; ② give them the static IP of our PBX — it is shown on the "Server" tab in the Telephony section; ③ hand over the list of numbers and the direct dial-in rule; ④ ask for the written interface description (rajapintakuvaus) and use it to verify transport, codecs, authorisation mode and the incoming number format; ⑤ ask them to pass media to UDP ports 10000–20000.

⚠️ The carrier is regional and its own numbering is 06…. Confirm before ordering that they sell outside their area and can provide numbers from other zones. JNT also has a retail service called MultiVoice — a SIP username and a 06… number for about four euros a month: that is not a trunk with direct dial-in, but it does work as a single line in the PBX.

Line Carrier — IP PBX Interface#

A Finnish "smart telco" that deliberately sells trunks to businesses with a third-party fixed PBX: "the service routes voice traffic from IP-based PBXs and suits businesses that prefer a fixed PBX service instead of a mobile PBX". The number of channels is free to choose; service and corporate numbers 010, 020, 0800 are sold separately.

The carrier's own articles state that a carrier-grade interface is delivered through a session border controller (SBC) and that trunk authorisation may be by IP address, by username and password, or both at once — which one you get is set in the contract.

What to set up with the provider: ① order the IP PBX Interface for the number of channels you need; ② state that the PBX is Asterisk on a dedicated cloud server with a static public IP, not inside the carrier's network; ③ hand that address over for the allowlist; ④ agree the numbers, service numbers included; ⑤ request the interface description.

⚠️ The company is small, sales go through an account manager only, and the portfolio also contains their own products (mobile PBX, contact centre) — a quote easily drifts towards those. Write it plainly in the request: you need a channel to your own PBX, without their add-ons.

Elisa — IP Vaihdeliittymä#

The largest Finnish carrier. The product is described precisely as an interface for a third-party system: "a SIP-based voice connection in which the voice channel of a company's communication system or service is connected to the public telephone network", plus explicit support for connecting public cloud services under the "bring your own carrier" model (Teams, ACS, Genesys Cloud). The size of the connection is set by the maximum number of simultaneous calls. Prices are not published; ordering goes through sales.

What to set up with the provider: ① order IP Vaihdeliittymä for the number of channels you need; ② hand over the static IP of our PBX for the allowlist; ③ demand the written interface description; ④ point the numbers you bought at this trunk.

⚠️⚠️ The first question to the account manager is about encryption. Elisa writes that "voice in cloud services is delivered over an encrypted protocol". If that means the interface is offered over TLS with encrypted media only, our PBX cannot connect to it — why. ⚠️ The second risk: the product is normally sold as part of a corporate bundle (the Elisa network, Teams), and "a trunk to our PBX in someone else's cloud" is an unusual request for sales.

DNA — VoIP-vaihdeliittymä#

The third large carrier, and its product wording is the most convenient of the big three: "a cost-effective way to connect IP PBXs and other similar communication systems to the public telephone network", with the connection running "either over an IP data connection or over the internet". That means DNA's corporate network is not mandatory — the public internet will do, which is our case. Capacity grows on demand, and resilience is built by duplicating the network connection.

What to set up with the provider: ① order VoIP-vaihdeliittymä for the number of channels you need and explicitly choose delivery over the internet; ② hand over our static IP; ③ point the numbers at the trunk; ④ request the interface description and verify transport, codecs and the incoming number format against it.

⚠️ DNA pushes its own PBX service hard — state in the request that you need a trunk to an external PBX, not their cloud exchange.

Contract-only carriers#

These carriers have or claim a trunk, but the product is not public enough to build a card with a table around it. The procedure is the same: request a quote, obtain the interface description, and enter the values you receive into the same "Add provider" form.

• Telia Finland. The incumbent; there is no public trunk page, and the product name — Puheväylä — is known from partner documentation, where the customer is asked to state "the SIP port on the Telia side" and their numbering plan. So the trunk exists and its parameters are issued during the connection project. The Touchpoint PBX service closed on 31 March 2026 and was replaced by Telia Smart Connect — that is a cloud exchange, not a trunk; do not confuse the two when talking to sales.
• Somic. A systems integrator in Espoo and Turku: "VoIP-vaihdeliittymä eli SIP-trunk" plus Teams integration, call recording and voice menus. Judging by the site, they resell a carrier trunk. Ask for the channel as it is, without their add-ons, and say up front that the PBX is Asterisk in a cloud with a static IP.
• Tele1. A small carrier: "SIP-Vaihdeliittymä carries VoIP traffic from a company's IP PBX both to fixed-network subscriptions and to mobiles". They also sell corporate numbers 010, 020, 029 — a convenient alternative to a landline number. ⚠️ The website has not been updated for a long time: check that the company is still trading before you sign.
• Setera. A Finnish carrier with an international bent: its own operator licences in more than 20 countries and numbers in 60+ countries. The storefront shows a cloud PBX, voice for Teams/Zoom/Webex and an SMS gateway; there is no separate "trunk to your PBX", but there is a carrier-facing offer to "connect your platform to Setera's international network". Interesting if you need a Finnish number and numbers in neighbouring countries under one contract.
• Cuuma. A Finnish customer service platform with its own exchange and a "numbering" product; they state plainly that they also sell voice traffic and mobile subscriptions. There is no "trunk to your PBX" product on the site — ask them directly.

Which trunks will not work with our PBX#

• Any interface offered over TLS with encrypted media only. Our PBX supports UDP and TCP on trunks and has no encrypted transport — see Network and compatibility. This is the main risk with Elisa, which stresses the encrypted protocol for cloud connections. Ask for an ordinary UDP or TCP interface.
• A trunk delivered only inside the carrier's own network (a VPN or a closed corporate network) with no exit to the public internet. Our PBX lives in a cloud and has no access line in a Finnish office, so there is nothing to connect such a trunk to. The direct question for the account manager: "do you sell the trunk to our public static IP address, without your access line?" For DNA and JNT the service description answers yes.
• Enreach. Sells its own telephony: a cloud exchange, voice for CRM and Teams, call analytics; subscriptions run on top of the Telia, DNA or Elisa networks. There is no trunk to an external PBX — the direction is the opposite of ours.
• Ålcom (Åland Islands). Corporate telephony is cloud exchanges only. A +358 18… number is bought from them, but it can be brought into our PBX only if they agree to provide a trunk, or by porting the number to a mainland carrier.
• Telavox Finland. The trunk is documented by the group's Danish arm, not the Finnish one; in Finland the company positions itself as a business-only mobile carrier with its own exchange. "Not documented" with such carriers usually means an incident will be closed with the words "not supported".
• Ainacom. It appears in older lists of Finnish SIP providers but is no longer a carrier: as of 09.09.2026 the domain hosts an unrelated service. From the same outdated list: Sonera is today's Telia Finland, and TDC Finland was absorbed long ago.

International providers with Finnish numbers#

Finnish numbers are sold by every large international aggregator; their hosts, modes and quirks are in the catalogue cards and the overview. Only the country-specific part is here.

⚠️⚠️ The limitation that makes this route only partly usable. Holding a Finnish number at an international aggregator for inbound calls is fine: the call reaches our PBX over their trunk and bothers nobody. But outbound calls into Finland with a Finnish number in the CallerID over an international interconnect are explicitly forbidden by the regulator's rules, and the Finnish carrier at the far end is obliged to block such a call. In practice:

• if you only need inbound calls (guests calling the venue), an international aggregator works and the number activates within hours;
• if you need outbound calls "from our Finnish number", the trunk has to come from a Finnish carrier from the sections above;
• the middle ground is to receive calls on the international number and dial out without a Finnish number in the CallerID (the aggregator's own number will be presented). Leave the Present as field empty in that case.

Number porting#

• Deadline. Porting a number from the donor carrier to the recipient carrier may take no more than five working days. The clock starts when the recipient carrier has sent the porting data to the donor and stops when the number works technically in the recipient's network.
• Service interruption during porting must not exceed 10 minutes for mobile services and 60 minutes for fixed ones.
• Who files the request. Porting is initiated by the recipient carrier — the one you sign the new contract with. It does not depend on the type of the old contract or on its notice period.
• Geography. A geographic number ports within its own numbering area; in Uusimaa a number ports between both areas (9 and 19). Carriers exchange porting data through the shared industry porting system.
• ⚠️ A number bought from an international aggregator will not move to a Finnish carrier so easily: porting from abroad is possible only if the receiving Finnish carrier agrees to it. If you plan "a quick international number first, a real trunk later", expect the number to change.

Rules and paperwork#

If it does not work#

General symptoms and how to read a SIP trace are in the overview section If calls do not go through.

Frequently asked questions#

Can we buy a Finnish number from Telnyx or Zadarma and call Finnish guests from it?#

Receiving calls — yes, that works. Calling Finns while presenting that number — no: the regulator's rules forbid releasing a Finnish number as CallerID from abroad and require carriers to block such calls. Outbound calls from your own Finnish number need a Finnish carrier's trunk.

Do we need a telecommunications licence?#

No. The notification to the regulator is filed by whoever provides communications services professionally — your provider. The venue stays a subscriber and buys the channel and the number under an ordinary contract.

How long does connection take?#

An international number activates within hours or days. A Finnish trunk takes weeks: sales, contract, connection project. Porting a number you already have takes up to five working days. If the number is needed "by tomorrow", start with an international one and order the Finnish trunk in parallel.

What is a rajapintakuvaus and why demand it?#

It is the written description of the interface through which a customer connects their own equipment to the carrier's network; the regulator requires carriers to have one. That document holds the host, port, transport, codecs, authorisation method and incoming number format — everything that goes into the trunk form. It is the lawful argument against "parameters come with the project".

We have several venues in different cities — do we need a landline number in each area?#

Not necessarily. National numbers (010…, 020…, 029…, 075…) are common for Finnish businesses: they are not tied to a city, so all venues can sit behind one number with routing inside the PBX. A landline number helps if your guests are used to the local area code.

What about a venue in the Åland Islands?#

Åland is the same country and the same +358 code, but it has its own area code 18 and its own carrier, which offers no public trunk to a third-party PBX. Your options: negotiate with them separately, take a number from a mainland carrier from the sections above, or use an international number for inbound calls.

Sources#

All links were checked on 9 September 2026.

Regulator and rules

• Määräys 32 V/2025 M — numbering of the public telephone network (PDF): https://www.traficom.fi/sites/default/files/media/regulation/M_32_V_2025.pdf
• Määräys 28 L/2025 — interoperability of communications networks and services, CallerID and blocking rules (PDF): https://www.traficom.fi/files/media/regulation/M_28_L.pdf
• Määräys 46 L/2023 M — telephone number portability (PDF): https://www.traficom.fi/files/media/regulation/M_46_L_2023.pdf
• Traficom — numbering of the telephone network: https://www.traficom.fi/fi/viestinta/laajakaista-ja-puhelin/puhelinverkon-numerointi
• Traficom — filing a telecommunications activity notification: https://www.traficom.fi/fi/viestintaverkot/teletoiminta/tee-teletoimintailmoitus

Carriers

• JNT — SIP-trunk IP-vaihdeliittymä (prices, channels, static IP): https://www.jnt.fi/fi/yrityksille/palvelumme-yrityksille/puhelinpalvelut/sip-trunk-vaihdeliittyma/
• Line Carrier — IP PBX Interface (SIP Trunk): https://www.linecarrier.fi/en/smart-telco/ip-pbx/
• Line Carrier — what an IP-vaihdeliittymä is: https://www.linecarrier.fi/artikkelit/mika-on-ip-vaihdeliittyma/
• Elisa — IP Vaihdeliittymä (SIP trunk): https://yrityksille.elisa.fi/ip-vaihdeliittyma
• DNA — VoIP-vaihdeliittymä (SIP trunk): https://www.dna.fi/yrityksille/asiakaspalveluratkaisut/voip-vaihdeliittyma
• Telia — customer service and telephone exchange: https://www.telia.fi/yrityksille/palvelut/asiakaspalvelu-ja-puhelinvaihde/touchpoint
• Sinch Contact Pro — connecting Telia SIP trunks ("Telia Puheväylä in Finland"): https://docs.cc.sinch.com/cloud/service-configuration/en/ehp1622544624174.html
• Somic — VoIP-vaihdeliittymä eli SIP-trunk: https://somic.fi/voip-vaihdeliittyma/
• Tele1 — products (SIP-Vaihdeliittymä): http://tele1.fi/?page_id=36
• Setera — services for business: https://setera.com/fi/palvelut/
• Enreach Suomi — telephone exchange: https://www.enreach.fi/fi/puhelinvaihde
• Cuuma Communications — products: https://cuuma.com/tuotteet/
• Ålcom — exchange services: https://www.alcom.ax/foretag/telefoni/vaxeltjanster

International providers

• DIDWW — regulatory requirements, Finland: http://www.didww.com/resources/regulatory-requirements/Finland
• Telnyx — Finland DID requirements: https://support.telnyx.com/en/articles/5465874-finland-did-requirements
• Twilio — Finland regulatory guidelines: https://www.twilio.com/en-us/guidelines/fi/regulatory
• Zadarma — Finnish phone numbers: https://zadarma.com/en/tariffs/numbers/finland/

Related pages#

• Connecting a provider's number to the PBX — the general steps, trunk modes, network and link testing.
• Setting up SIP phones — how to connect desk phones and DECT to extensions.