Slovenia: SIP providers and connecting a number to the PBX

This page continues the general guide on connecting a provider number to the PBX: that page covers everything that is the same for any operator — the two trunk modes, what to ask the provider, what to type into the form, network requirements and the connectivity check. Here is the Slovenian specifics: who sells a number with a SIP trunk in the country, what that operator issues and what of it goes into Telephony → “Trunks and connections” → “Add provider”.

The data was collected on 9 September 2026 from operator service pages, the Telekom Slovenije regulated reference offer and materials of the regulator (AKOS); links are in “Sources”.

In brief#

• You can buy a number with a SIP trunk in Slovenia, and the venue needs no permits for that. There is no VoIP licence in the country: an operator notifies AKOS in writing, the agency enters it into the register within seven days — and you stay an ordinary subscriber. The number and the trunk are bought from a Slovenian operator by the venue itself.
• The main local trait: nobody publishes trunk parameters. Five operators sell a trunk for your own PBX — T-2, Telekom Slovenije, A1, Telemach, SoftNET — yet none of them publishes a server address, a port, codecs, or even the answer “REGISTER or IP”. No Slovenian operator publishes an Asterisk guide either. Plan the connection as a conversation with an engineer plus a test, not as “copied from the docs and done”.
• The network is compatible nevertheless, and that is documented. The Telekom Slovenije regulated reference offer RIO IP v12.0 (in force since 01.09.2025) states the network voice profile directly: G.711 A-law as the mandatory codec, 20 ms packetisation, DTMF per RFC 2833, signalling port 5060, media over UDP only, signalling over UDP or TCP, the number in the SIP URI in E.164 without the “+”. The PBX does all of that. The caveat: RIO is an offer for operator interconnection, it maps onto a retail trunk by analogy only — so confirm the final values with the engineer.
• If the operator is not chosen yet, start with T-2. It is the only operator in the country that has publicly named the transport (“SIP over UDP or TCP”), with a minimum of 4 voice channels; in August 2026 it became the first and so far the only certified Yeastar SIP trunk provider in Slovenia, which means a trunk to a third-party PBX is a routine scenario for it. Ask SoftNET second: a corporate operator for which trunking is a core product rather than a package add-on.
• The trunk is almost always sold bundled with the operator's own access. At Telekom Slovenije “Govorni dostop” is described as a connection over their IP/MPLS network; at Telemach and A1 the trunk sits inside a business bundle. “PBX in the cloud, trunk over plain internet” is not advertised by anyone — it is a negotiation item, and it must be the first question, before signing.
• Local pitfall: the Slovenian national number is 8 digits, while a line is matched by the last seven. The Ljubljana 01 234 56 78 and the Maribor 02 234 56 78 produce the same tail; the same happens with mobile 041 … and 031 …. As long as the venue's numbers come from one zone, everything is fine.
• Paperwork. The contract is signed with a Slovenian entity (matična / davčna številka); none of the operators publishes a procedure for a foreign company. A foreign company gets a +386 number faster from an international provider.

Numbers in the country#

• Country code +386, international prefix 00 (or +). The national significant number is exactly 8 digits; inside the country it is dialled with a leading zero (0 + 8 digits), which is not part of the international form.
• Geographic numbers — 1 zone digit + 7 subscriber digits. Zones: 1 Ljubljana, 2 Maribor and Murska Sobota, 3 Celje, 4 Kranj, 5 Nova Gorica, Koper and Postojna, 7 Novo mesto and Krško.
• Mobile numbers — 2 prefix digits + 6 digits (03X/04X/05X/06X/07X nationally): 030, 031, 040, 041, 051, 064, 068, 069, 070 are in use.
• Toll-free 080 and premium 090 are sold as a separate product — both T-2 and A1 have them.
• Emergency numbers: the pan-European 112, police 113, the European missing children hotline 116 000. The operator must pass the caller's number and location to the competent authorities, and such calls are recorded.

On the “Lines” tab the number may be entered in any form: the PBX matches the last seven digits. ⚠️ In Slovenia seven digits mean the number without its first digit, and the first digit is exactly the zone code (or the second digit of the mobile prefix): numbers from different zones share a tail, and lines then cannot be told apart by DID (the call is still accepted — only the line choice is lost). If the venue holds Ljubljana and Maribor numbers at once, check the tails by hand — “Add the number and routing”.

⚠️ Emergency numbers are shorter than four digits. The catch-all outbound rule “everything else goes through this trunk” does not pick them up: add explicit-pattern rules for 112 and 113 on the “Outbound” tab.

Who sells a number with a SIP trunk#

The cards below cover the two operators whose network profile is at least partly published: T-2 (transport named outright) and Telekom Slovenije (the network voice profile is in the regulated offer). The other local operators disclose everything only after a contract — see “by contract”.

T-2#

An alternative operator from Ljubljana (Verovškova 64a) with its own fibre and mobile network. The service is called “Povezava obstoječe telefonske centrale” (“IP telefonska centrala” in the menu): the customer's IP PBX is attached to the T-2 network in a point-to-point arrangement. Connection is free; the subscriber pays a monthly fee for the gateway with the required number of active voice channels plus outbound traffic at the price list, metered on the T-2 call server.

This is the only operator in the country that says anything technical about attaching a third-party PBX: “IP prenosnik s SIP (UDP ali TCP) ali H.323 protokolom”, an arbitrary number of channels but no fewer than four. The trunk carries CLIP/CNIP, CLIR/CNIR, call forwarding, call transfer, call waiting and hold, internal dialling, DDI and three-party conferencing. One more argument: since August 2026 T-2 is the first and only certified Yeastar SIP trunk provider in Slovenia; for us that is not a ready template (our PBX does not read Yeastar templates) but proof that a trunk to somebody else's PBX is a rehearsed scenario there and the customer's integrator keeps their own PBX.

What to enter in the admin panel

What to set up at the provider: order “Povezava obstoječe telefonske centrale” → state the number of voice channels (no fewer than 4) → hand over the static IP of your PBX → request the number format in the incoming call and the codec list → point the purchased numbers (the DDI range) at the trunk.

Pitfalls ⚠️ “Način točka-točka” at T-2 means a link into their network, not a public SIP endpoint: ask straight away whether a PBX in someone else's cloud over plain internet qualifies. The Yeastar certification does not replace an answer about Asterisk — ask for the parameters explicitly, referring to it. And do cap the outbound destinations and the number of simultaneous calls on the operator's side: on Slovenian forums a hacked PBX with an open trunk and a bill of several thousand euros is a recurring story. Source: T-2, “IP telefonska centrala”, Telecom Reseller, “T-2 Becomes the First Certified Yeastar SIP Trunk Provider in Slovenia” (28.08.2026) — 09.09.2026.

Telekom Slovenije — “Govorni dostop”#

The incumbent (formerly SiOL) and the largest holder of numbering. The service wording is exactly our case: “omogočamo priključitev hišnih IP-central na javno telefonsko omrežje. Storitev temelji na SIP-povezavi med hišno centralo naročnika in strežniki v omrežju Telekoma Slovenije.” Ordering goes through the “Oddaj povpraševanje” form; there is no public price list. Capacity is licensed in bundles: “Govorni dostop 10” means 10 voice channels for up to 30 users, and the connection runs over the Telekom IP/MPLS network with prioritised voice.

What to enter in the admin panel

What to set up at the provider: order “Govorni dostop” of the required capacity (channels = licences) → agree the point of attachment (their IP/MPLS versus plain internet — the key question) → hand over the static IP of your PBX → point the numbers at the trunk.

Pitfalls ⚠️ The product is sold together with their own access — “just a trunk over the internet” has to be negotiated separately. Capacity is counted in “channels / users” pairs (10 channels = up to 30 users), and your PBX extensions count as users. There is no public price list, everything goes through a salesperson. Source: Telekom Slovenije, “Govorni dostop” — 09.09.2026.

Providers “by contract”#

These operators do have a trunk for a third-party PBX and sell it as a regular product, but the server address, the authorisation mode, the login and the password are issued only after a contract — so there can be no “what to enter” table here. Ask for the parameters using the list in “What to ask the provider” and type them into the same form as for the others. Spell out the main point separately: the PBX sits in the cloud, not on the venue's premises — get that confirmed in writing before paying.

• A1 Slovenija — “A1 PBX”. A service for companies “ki že imajo ISDN ali IP hišno centralo”: the operator explicitly promises “primerno število govornih kanalov (SIP trunk) za priključitev na javno omrežje”, channels start from two, the connection fee is subsidised in exchange for contract term, and there is an A1 PBX Total bundle with unlimited calls to all Slovenian and EU networks (special and premium numbers excluded). ⚠️ The service model is “we will come and configure your PBX” (“v celoti poskrbimo za namestitev ali nadgradnjo obstoječih hišnih central”): ask explicitly for “samo SIP trunk parametri, centralo upravljamo sami”, otherwise the engineer will expect access to the PBX.
• Telemach Slovenija — “SIP trunk”. Verbatim: “Uporabnikom, ki imajo lastno centralo IP, SIP trunk omogoča priklop sodobnih telefonskih sistemov na javno telefonsko omrežje operaterja. SIP trunk je dodeljen številkam linij, ki jih naročnik dobi v uporabo” — that is, the trunk is bound to the line numbers. It is sold inside the “Biznis” business bundles; next to it in the catalogue sit their own IP Centrex and virtual PBX, so ask for the trunk specifically. ⚠️ Telemach telephony has historically been tied to their own cable access — put the cloud-PBX question first.
• SoftNET informacijske infrastrukture. A corporate operator with its own network in seven countries of the region (SI, HR, RS, BA, MK, RO, BG); “SIP trunking” sits in the catalogue next to “IP Centrex” and “On site IP-PBX”, so a PBX on the customer's premises is routine for them. The most likely candidate to hand over the parameters and accept your static IP. ⚠️ Whether they hold Slovenian numbering of their own or resell it is not stated on the site — ask when ordering; there is no public price list.
• Who does not offer a trunk. Mega M (MegaTel) sells mobile, internet and TV, with no “priklop lastne centrale” product on the site. Novatel with its Voipex product and Owify are ready-made cloud PBX and contact-centre platforms with their own web client — your own PBX cannot be attached to them. Detel Global is bankrupt and its site is down.

International providers with Slovenian numbers#

None of the Slovenian operators offers online ordering or prepaid service — the contract always goes through a salesperson. That is why for a foreign company (and for a quick pilot) an international provider is often the only way to get a Slovenian number today.

• Twilio — the only “preferred” provider in the 3CX list for Slovenia, and its requirements are published item by item. For landline numbers you need an address inside the number's prefix zone (a PO box is not accepted) plus evidence: a trade register extract with the local address, a utility bill, a tax notice, a lease agreement or a proof of ownership. For mobile numbers (+386 31) there are no requirements at all — neither for a company nor for an individual. That is the fastest legal path: a Slovenian mobile number with no paperwork.
• DIDWW — Slovenian landline numbers are published by city: Ljubljana, Maribor, Celje, Kranj; the country page carries a regulatory requirements section with the documents.
• Telxi — the second and last entry in the 3CX list for Slovenia, in the “supported” category; its 3CX card states SIP TLS support and the requirement to enter the main trunk number in E.164. ⚠️ Our PBX does not support TLS trunks — make sure when ordering that the provider offers UDP or TCP.
• Telnyx, Plivo, Bandwidth, Sinch, Infobip, Zadarma advertise EU-wide coverage, but check the availability of Slovenian numbers in the account search: we did not verify the Slovenian inventory item by item.

The parameters and modes of these providers are already described in the catalogue when adding a provider — the server address and the mode are filled in for you, no need to copy them from the country page.

⚠️ Emergency calls. With international providers 112 is a separate service and is not available everywhere. For a venue that must stay reachable for emergency services this argues for a local operator.

Number porting#

• Porting works and it is fast. Under the general act on number portability the number must be activated at the new operator within one working day of it receiving the signed porting agreement, and the fee per request is capped at the actual cost — in the wording of the act known to us, no more than €5. Confirm the current wording and the current price with the operator: the act was adopted under the previous electronic communications law.
• Porting is initiated by the receiving operator — the request is filed with them together with the trunk order. Each operator has its own form: A1 uses MNP_Obrazec, T-2 has an “Ohranitev telefonske številke” section.
• The number is ported, the service is not. The trunk at the new operator is provisioned from scratch, and for a while the old one is still alive — in that window incoming calls may go the wrong way. Agree the date in advance and keep both trunks enabled in the PBX.
• A geographic number is tied to its zone: porting keeps the zone, but you cannot “move” a Ljubljana number to Maribor — there you need a new number.
• A number registered to an individual requires a change of subscriber before it can be ported to a company — that is a separate procedure, done before the porting request.

Rules and paperwork#

If it does not work#

1. The operator talks about connecting “over our network” while the PBX is in the cloud. This is the country's main fork: at Telekom Slovenije the service is described over IP/MPLS, at Telemach and A1 it lives inside a business bundle. Insist on a publicly routable SIP host reachable from the cloud, and settle this before signing.
2. You do not know why there is no registration. The authorisation mode is published by no Slovenian operator — ask in writing: Avtorizacija: REGISTER (uporabniško ime/geslo) ali po IP naslovu?. With IP authorisation the login and password are not needed, but the operator must be given the “Static IP” from the “Server” tab, and the operator's address goes into the “SIP host” field.
3. The provider offers TLS only or G.729 only. Such a pairing will not work: the PBX speaks UDP and TCP and understands G.711 a-law/u-law and G.722 — see “Network and compatibility”. Ask for G.711 A-law: in the Slovenian fixed network it is mandatory under the incumbent's offer.
4. The call connects but there is silence — a codec the PBX does not have was negotiated, or media does not arrive. Check the address and the port with “Check connection” and confirm the codec in writing.
5. Two numbers land on the same line. The last seven digits of a Slovenian number omit the first digit — the zone code: 01 234 56 78 and 02 234 56 78 share a tail. Separate such lines manually or take numbers from a single zone.
6. 112 or 113 cannot be dialled. Short numbers are not picked up by the catch-all outbound rule — add explicit-pattern rules for them.
7. A1 asks for access to your PBX. That is their standard model (“we will configure your PBX ourselves”). The answer: the PBX is ours and in the cloud, we only need the trunk parameters.
8. A Telemach link does not open. Part of the site has moved: poslovni.telemach.si now leads to telemach.si/poslovni/, and the trunk page itself is script-rendered — ordering by phone or e-mail is easier.

Causes that do not depend on the country are in “If calls do not go through”; the trunk modes and their differences are in “Two trunk modes”.

FAQ#

Which operator should I approach if nothing is connected yet?#

The calling order is T-2 → SoftNET → Telekom Slovenije → Telemach → A1. T-2 first, because it is the only one with a publicly named transport (SIP over UDP or TCP), a Yeastar certification for third-party PBXs and a low threshold of 4 channels. SoftNET second — a corporate operator for which trunking is a core product and a PBX on the customer's premises is routine.

What should the first e-mail to the operator say?#

The verbatim list, otherwise it takes three rounds: Ali lahko SIP trunk priključimo na lastno centralo (Asterisk) v oblaku, s statičnim javnim IP? · Avtorizacija: REGISTER ali po IP naslovu? · SIP strežnik (gostitelj), vrata, transport (UDP/TCP)? · Podprti kodeki, ali je G.711 A-law privzet? · V kakšni obliki prihaja klicana številka v Request-URI? · Koliko sočasnih klicev je vključenih in kako se dokupujejo? · Kako nastavimo prikaz številke (CLI) za odhodne klice?

Do I need a Slovenian company to get a number?#

For a local operator, yes: the contract is signed with a Slovenian entity holding matična and davčna številka, and none of the four publishes a procedure for a foreign company. A foreign company gets a +386 number faster from an international provider: at Twilio a Slovenian mobile number requires no documents at all, while a landline one needs an address in the prefix zone.

How many channels should I order?#

A channel is one simultaneous conversation; a venue usually needs 2–4. Mind the operators' thresholds: T-2 requires a minimum of 4 channels, A1 starts at 2, and Telekom Slovenije sells licences in bundles (“Govorni dostop 10” — 10 channels for up to 30 users, and your PBX extensions count as users).

Will calls to 112 work through the trunk?#

With a local operator, yes — it is their legal duty; they also record such calls and pass the number and location to the competent authorities. On our side all you need is an outbound rule with an explicit pattern for short numbers. With international providers emergency calling is a separate service and is not available everywhere.

Why do Slovenian operators have no Asterisk guide?#

The market is closed: parameters are treated as part of the contract, and the 3CX catalogue for Slovenia holds just two entries — Twilio and Telxi, both international. That does not mean your own PBX will not fit: a T-2 trunk with Asterisk is described by a customer on a local forum, and the incumbent's network is compatible with our profile per its published offer. The parameters simply have to be obtained by e-mail rather than from a web page.

Sources#

All links checked on 09.09.2026.

Operators

• T-2 — IP telefonska centrala (priklop obstoječe centrale): https://www.t-2.net/ip-telefonska-centrala
• T-2 — SIP klient (poslovna ponudba): https://www.t-2.net/poslovni/ponudba/telefonija/sip-klient
• Telekom Slovenije — Govorni dostop: https://www.telekom.si/velika-podjetja/telefonija/govorni-dostop/
• Telekom Slovenije — RIO IP v12.0 (PDF, in force since 01.09.2025): https://www.telekom.si/media/4drdbkig/rio-ip-v120_objava-javna-182025_cistopis.pdf
• Telekom Slovenije — RIO, medomrežno povezovanje s fiksnim omrežjem: https://www.telekom.si/veleprodaja/domaca-veleprodaja/vzorcne-ponudbe/rio-medomrezno-povezovanje-s-fiksnim-omrezjem
• A1 Slovenija — A1 PBX: https://www.a1.si/poslovni/telefonija-in-storitve/fiksna-telefonija/a1-pbs
• A1 Slovenija — Celovita poslovna telefonija: https://www.a1.si/poslovni/telefonija-in-storitve/fiksna-telefonija/celovita-poslovna-telefonija-a1
• Telemach — SIP trunk: https://poslovni.telemach.si/telefonija/sip-trunk/
• Telemach — Stacionarna telefonija in internet (poslovni): https://telemach.si/poslovni/poslovna-komunikacija/stacionarna-telefonija-in-internet
• SoftNET — SIP trunking: https://www.softnet.si/sip-trunking/
• Novatel — IP telefonija (Voipex): https://novatel.si/ip-telefonija/
• Owify: https://owify.si/
• Mega M / MegaTel: https://www.megatel.si/

Regulator and numbering

• AKOS — Agencija za komunikacijska omrežja in storitve RS: https://www.akos-rs.si/
• AKOS — Številski prostor (numbering plan and register): https://www.akos-rs.si/telekomunikacije/raziscite/stevilski-prostor
• AKOS — Registracija operaterjev: https://www.akos-rs.si/telekomunikacije/raziscite/registracija-operaterjev
• SPOT / gov.si — Zagotavljanje elektronskih komunikacijskih omrežij in storitev: https://spot.gov.si/sl/dejavnosti-in-poklici/dejavnosti/zagotavljanje-elektronskih-komunikacijskih-omrezij-in-storitev/
• Splošni akt o prenosljivosti številk (Ur. l. RS 2005): https://www.uradni-list.si/glasilo-uradni-list-rs/vsebina/2005-01-3368/splosni-akt-o-prenosljivosti-stevilk
• AKOS Mipi — Spoofing: telefonska prevara: https://www.mipi.si/187spoofing171-telefonska-prevara-ki-lahko-ujame-tudi-najbolj-previdne

International and industry

• 3CX — Supported SIP Trunk / VoIP Providers in Slovenia: https://www.3cx.com/partners/sip-trunks/slovene/
• Twilio — Slovenia: Regulatory Guidelines: https://www.twilio.com/en-us/guidelines/si/regulatory
• DIDWW — Slovenia local numbers: https://www.didww.com/phone-numbers/all-phone-numbers/Slovenia/Local
• Telecom Reseller — T-2 Becomes the First Certified Yeastar SIP Trunk Provider in Slovenia (28.08.2026): https://telecomreseller.com/2026/08/28/t-2-becomes-the-first-certified-yeastar-sip-trunk-provider-in-slovenia/

Related pages#

• Connecting a provider number to the PBX — the general steps, trunk modes, network, connectivity check.
• Setting up SIP phones — connecting desk phones and DECT to extensions.