Croatia: SIP providers and connecting a number to the PBX

This page continues the general guide on connecting a provider's 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 how to verify the link. Here is the Croatian specifics: who sells a number with a SIP trunk in the country, what such an operator hands over and what of it goes into Telephony → "Trunks and connections" → "Add provider".

The data was collected on 9 September 2026 from operator documentation, service terms and regulator (HAKOM) materials; links are in the "Sources" section.

In short#

• You can buy a number with a SIP trunk in Croatia, and the venue needs no permits for it. There is no VoIP licence in the country: the operator files a prior notification ("prethodna obavijest") with HAKOM and starts working, and you are simply its subscriber. The venue buys the number and the trunk from a Croatian operator itself.
• The country's main trait: nobody publishes the parameters. Not a single active Croatian operator publishes the server address, port and codecs — everything is handed over at provisioning time, by an engineer's e-mail or in the customer portal. Plan the connection as "correspondence with an engineer plus a test", not as "copy it from the docs and go".
• The market splits in two, and this is the main fork. Access operators (A1, Telemach, Hrvatski Telekom) have historically sold the SIP trunk as an ISDN replacement on top of their own fibre: in the only official Asterisk guide found in the country (Optima Telekom, now Telemach) the server address is a private 10.160.4.8, unreachable from the cloud. The second tier (TOP VoIP, Signum/Telefonika, SKVID) delivers the trunk "over any internet connection" — exactly what a cloud PBX needs.
• If the operator has not been chosen yet, start with TOP VoIP: the only one in the country with a public trunk price (€49–59 per month), free testing and no mandatory number porting. All four providers with cards below work in registration (REGISTER) mode.
• Codecs are not a problem. The mandatory codec of the Croatian fixed network is G.711 a-law, which the PBX supports; G.722 is allowed by the network as an option.
• Caller ID spoofing is banned by law, not merely "discouraged": the Electronic Communications Act (ZEK, art. 48) explicitly forbids false presentation of the caller. A1 enforces it technically — a number outside the contract range is either replaced by the "Glavni broj" or the call is blocked.
• Paperwork. The contract is signed with a Croatian legal entity or a sole trader (obrt) holding an OIB; a private individual will not be sold a business trunk. A foreign company without a Croatian registration will find it easier to take a +385 number from an international provider.

Numbers in Croatia#

• Country code — 385, international prefix 00 (or +). The national prefix 0 is not part of the number: Zagreb's 01 2345 678 is +385 1 2345 678 internationally.
• Geographic numbers. Zagreb and Zagreb County — code 1, national number exactly 8 digits (1 plus 7 subscriber digits). The other counties have two-digit codes: 20 Dubrovnik, 21 Split, 22 Šibenik, 23 Zadar, 31 Osijek, 32 Vukovar, 33 Virovitica, 34 Požega, 35 Slavonski Brod, 40 Međimurje, 42 Varaždin, 43 Bjelovar, 44 Sisak, 47 Karlovac, 48 Koprivnica, 49 Krapina, 51 Rijeka, 52 Istria, 53 Lika; the national number is 8–9 digits.
• Mobile — 91–99 and 90x, national number 9 digits.
• Toll-free — 800 and 801 (7–9 digits). Premium rate — 60, 61, 64, 65, 69; universal access number — 72; personal number — 74, 75.
• Emergency: 112 (single European number), 192 police, 193 fire brigade, 194 ambulance, 195 maritime search and rescue centre, 1987 roadside assistance, plus the harmonised 116000, 116111, 116117, 116123.
• Dialling. Inside the country — 0 plus the national number (01 … for Zagreb, 021 … for Split); abroad — 00 and the country code.

On the "Lines" tab the number can be entered in any format: the PBX matches the last seven digits. ⚠️ In Croatia seven digits are exactly the subscriber part without the county code: Zagreb's 1 234 5678 and Rijeka's 51 234 5678 with the same subscriber part produce the same tail. As long as all of the venue's numbers come from one area this is fine; with numbers from different counties check the tails manually — "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: create separate rules with an explicit pattern for 112, 192, 193 and 194 on the "Outbound" tab.

Who sells a number with a SIP trunk#

The first four operators have cards below — their mode is known and it is clear what to enter. A1 documents its trunk rules more thoroughly than anyone in the country, but the authorisation mode is not named in the service terms, so it gets a section of its own. The remaining local operators release parameters only after a contract — see "under contract".

Telemach Hrvatska#

The "Business Trunking" product comes with three interfaces: ISDN BRA, ISDN PRA (up to 120 voice channels) and SIP — "for companies with a SIP-compatible PBX", with a flexible number of channels. Telemach inherited the product from Optima Telekom (the optima.hr domain now redirects to telemach.hr, and the support section still hosts "Optima dokumentacija"). This is the only operator in the country with an official Asterisk guide — an archived one, from 2019, and it is exactly what exposes the main trap.

What to enter in the admin panel

What to set up with the provider: order "Business Trunking" with the SIP interface → agree on the number of channels → port your numbers or get new ones → ask for a publicly routable SIP host and have the static IP of your PBX allowed on their equipment.

Pitfalls ⚠️ A private server address is fatal for a cloud PBX. The trunk is designed for the operator's own access line; if the engineer names an address in the 10.x range, the trunk will not come up, and this is the first question in the negotiations, before signing. In the Optima guide the caller number was carried in the P-Asserted-Identity header, while our PBX puts it in From — agree that they take the number from From, otherwise outgoing calls go out with no presentation or with the carrier's number. The codecs in the guide are alaw and G.729; the PBX has exactly one in common — G.711 a-law — and its presence on the trunk is worth confirming in writing. And most importantly: the parameters from the archived guide are a starting point for the conversation with the engineer, not ready-made truth. Source: Business Trunking, Optima — Upute za podešavanje Asterisk VoIP centrale (archived 22 Sep 2019) — 09.09.2026.

TOP VoIP#

A VoIP provider with a public SIP trunk price list — a rarity for the country: the Sip trunk S 1000 package costs €49 per month plus VAT and includes 1000 minutes to Croatian fixed and mobile networks and 5 voice channels; Sip trunk M 1500 costs €59 per month plus VAT with 1500 minutes and 15 channels. Beyond the bundle it is €0.0133 per minute to fixed and €0.0664 per minute to Croatian mobile networks; billing is per second from the first second, with no call setup fee, no multi-year contracts and no start-up fees.

The key difference for us: the trunk works over the internet rather than over their own access line — "ne trebate mijenjati vašeg postojećeg telefonskog operatora, niti ne trebate prenositi telefonski broj… sve što vam treba je pristup Internetu". Porting your number is not required: you may hand them outgoing traffic only. Third-party equipment is explicitly supported — "sva naša rješenja i usluge podržavaju standardnu modernu SIP opremu poznatih proizvođača".

What to enter in the admin panel

What to set up with the provider: request free testing → get the e-mail with the parameters and use it to capture the real host, port and codecs → pick the package by the number of channels → port the number if needed → confirm that your number is allowed in outgoing calls.

Pitfalls ⚠️ 5 channels in the entry package is few for a venue with a call queue: count a channel as one simultaneous conversation and take a package with headroom. The site is partly outdated — the news section has not been updated since 2018 and some neighbouring pages still quote prices in kuna — so confirm the price with an invoice rather than a web page. The provider does not publish its codecs: ask for G.711 a-law in writing. Source: SIP trunk — packages and prices — 09.09.2026.

Signum telekomunikacije (Telefonika)#

An "alternativni telekom operator u nepokretnoj mreži" aimed at business: the products are SIP Trunking ("for business customers who have their own SIP-compatible PBX", flexible channel rental instead of ISDN and E1), Cloud_PBX and DID Brojevi. The same company's low-cost retail brand is Telefonika.hr: a cloud PBX from €28 per month, DID numbers, prepaid billing, free testing and number porting "with one signature". Contacts: +385 1 3535 035, info@signumtel.hr.

What to enter in the admin panel

What to set up with the provider: request a test account → order the required number of channels and DID numbers (or port your own) → get the account parameters → confirm that registration is allowed from the public address of your cloud PBX.

Pitfalls ⚠️ The operator's instructions section only holds softphone guides (Grandstream Wave, Zoiper) — meaning the account is an ordinary SIP pair and the PBX works fine as a client, but you will still have to e-mail an engineer for the trunk parameters. Parts of the site are unmaintained: the copyright reads "2010-2024", some prices are in kuna and some Telefonika brand pages return 404 — call before signing up to make sure the service is alive. Telefonika's FAQ offers renting a geographic number of another city or country and presenting yourself with it — remember the ban on false caller presentation: in outgoing calls use only the numbers of your own contract. Source: SIP Trunking, Telefonika — Cloud PBX — 09.09.2026.

Tehnoline Telekom#

A local operator of Istria and Kvarner (Pula, +385 52 350 000, helpdesk 0800 2556). Alongside its own cloud PBX it offers the TehnoTel telecom service: "voice trunkovi s do 100 istovremenih poziva te prijenos postojeće numeracije ili dodjela novih nacionalnih i međunarodnih brojeva". The servers are in a Croatian data centre with a declared availability of 99.98%.

What to enter in the admin panel

What to set up with the provider: use "Zatraži ponudu" on the site → explicitly ask for a bare trunk to your own PBX, not for the operator's cloud PBX → agree on the number of concurrent calls → port your numbers or get new ones → clarify the public server address and have your PBX's static IP allowed.

Pitfalls ⚠️ The trunk is presented as an add-on to their own cloud PBX — unless you say otherwise up front, the quote will contain a Cloud PBX rather than a trunk. The operator is tied to its coverage area: for a venue outside Istria and Kvarner it only makes sense as a source of a number. Parameters and codecs are not published — confirm G.711 a-law in writing. Source: Cloud PBX / TehnoTel — 09.09.2026.

A1 Hrvatska — the strictest trunk rules#

Biz IP Trunking is the service for connecting your own IP PBX to the A1 network. It comes in three packages: paket SIP, paket H.323 and paket Remote (the last one is not a trunk but a way to attach IP phones at a remote site). The service provides DIDs on selected PBX lines, porting of existing geographic numbers or new A1 numbering, and a "Glasovni VPN" between sites; the number of channels is set in the order. Only a legal entity or an individual acting as an entrepreneur can be a subscriber.

There is deliberately no "what to enter" table here: A1 does not name the server address, the port or the authorisation mode in its public terms — they are issued at provisioning. Ask for the parameters using the list in "What to ask the provider", and separately clarify two things: whether it is REGISTER or IP authorisation (in the latter case give the operator the "Static IP" from the "Server" tab) and which SIP host will be publicly reachable from the internet. The network codecs are known: G.711 a-law (20 ms) is mandatory, G.729a and G.722 are optional — so the PBX talks to the A1 network without transcoding.

What you will have to decide when ordering — nobody else in the country asks this:

• Glavni broj. One number from the contract range is designated: it will be presented instead of an invalid caller number and will appear in the call detail records.
• Behaviour on an invalid caller number — your choice: substitute the Glavni broj or block the call. ⚠️ Blocking also applies to emergency calls, including 112: a venue with guests must not pick that option.
• The numbering area must match the real connection address — a Zagreb number may not be presented from a Split site, even if both numbers are yours.
• A site address per number — 112 is routed by it. When the venue moves, the address has to be updated with the operator.

Source: Biz IP Trunking, Uvjeti korištenja usluge Biz IP Trunking (PDF), Uvjeti IP međupovezivanja (PDF) — 09.09.2026.

Providers "under contract"#

These operators do sell a trunk for a third-party PBX as a standard product, but the server address, username and 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. State the main point separately: the PBX sits in the cloud, not on the venue's premises — get that confirmed in writing before paying.

• Hrvatski Telekom (Iskon brand). The public price list for business voice services contains the Net Phone PBX product, billed "po korisničkom računu (telefonskom broju)" — that is, IP telephony for the subscriber's PBX where an account is created per number. There is no separate public product page; the "Net Phone paketa" specification states plainly that the subscriber configures their own equipment "prema parametrima Hrvatskog Telekoma" and that the operator does not guarantee third-party equipment will work. ⚠️ The key question for the manager: one trunk account with DIDs or a separate account per number — in the latter case the PBX has to keep one registration per number. The Iskon brand has been part of HT since 1 January 2024 and has no trunk of its own.
• SKVID (S://VoIP). The "Govorni kanali — SIP & IAX trunking" product: a trunk to any IP PBX ("ako posjedujete bilo koju IP PBX telefonsku centralu, implementacija ove usluge je besplatna"), an arbitrary number of channels and DIDs, over the internet access of any operator. We only need the SIP interface; IAX is not used. ⚠️ The product is sold bundled with their own cloud PBX — explicitly ask for a bare trunk to a third-party PBX. There is no public price list: as of 09.09.2026 the pricing page returns a server error.
• SoftNET informacijske infrastrukture. An operator with a regional footprint (HR, SI, RS, BA, MK, RO, BG) selling SIP trunking, IP Centrex and on-site PBX. It has a wholesale branch and works with operators, so it is worth asking about IP authorisation: that suits us better — no password needed, just hand over your PBX's static IP. There are no prices or parameters on the site, everything goes through an engineer; for a single small venue this is probably not their customer size.
• Fibernet. The FIBER.BIZ business packages include only one "IP telefonska linija" with a bundle of minutes; there is no "SIP trunk to your own PBX" product in the public offer. Technically such a line is an ordinary SIP account, but the operator publishes neither the parameters nor permission to register it from a third-party PBX: if they agree to issue them, the fields are filled in like an ordinary registration trunk. Intersat, CloudPBX.hr and VoIPBON are the same story — publicly they only show a cloud PBX product, with no trunk facing outwards.

International providers with Croatian numbers#

Croatian numbers are sold by DIDWW, Telnyx, Twilio and Zadarma, as well as Sonetel and CommPeak. For a foreign company this is often the only route: local operators sign contracts with a Croatian entity (OIB), and none of them publishes a procedure for buying a number as a foreign company.

• Zadarma — local numbers by city: Zagreb +385 1, Split +385 21, Rijeka +385 51, Zadar +385 23, Istria +385 52, plus a toll-free 0800. Documents: a copy of the company registration certificate or a passport/ID (both sides) and an address in the region of the city whose number is ordered; an existing Croatian number can be ported free of charge.
• Telnyx — Croatia is in the list of country requirements: local numbers require business verification (representative's name, company name, a copy of an ID document, the registration certificate) and an address matching the DID area code, with supporting proof no older than three months; private use is not allowed, and activation after the check takes about 72 hours. For a toll-free number an address in Croatia is enough and an individual qualifies.
• DIDWW — Croatian local numbers by city plus toll-free, sold together with a local trunk for inbound and outbound; the requirement is the same — an address matching the area code and company documents.
• Twilio Elastic SIP Trunking — Croatia is on the country list, and a regulatory bundle is mandatory as everywhere in the EU. The modes are by IP or by credential list; there is no ordinary registration: you will need the PBX's static address from the "Server" tab.

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

⚠️ Emergency calls. With international providers 112 is a separate service and is not available everywhere, and only your own number may be presented in outgoing calls (in Croatia that is also a legal requirement). For a venue that must be reachable for emergency services this is an argument in favour of a local operator.

Number porting#

• The right to port is set by law (ZEK, art. 152): a subscriber may keep the number when changing operators, the service interruption may not last longer than one working day, the right to port survives contract termination for at least 30 days, and a minimum contract term may not be an obstacle to porting. The porting fee between operators must be cost-oriented.
• A geographic number ports only within the same location. Moving the venue from Split to Zagreb means a new number: the old one cannot be kept across counties. Porting between fixed and mobile networks is impossible as well.
• Operator practice matches the law: A1 promises free number porting or new numbers from its own range; Signum and Telefonika advertise "prijenos jednim potpisom"; TOP VoIP charges a porting fee depending on the service and lets numbers be taken back; Tehnoline ports existing numbering or issues new numbers.
• The application is filed with the new operator together with the trunk order — no separate visit to the previous operator is needed.
• The number is registered to whoever signs the contract. A business trunk is sold to a legal entity or a sole trader: if the number belongs to the venue, register it to the company right away, otherwise it will leave with the person when the business changes hands.

Rules and paperwork#

If it does not work#

1. Registration fails and the operator gave an address like 10.x. That is a private address inside their network: the trunk is meant to be reached over the operator's own access line and is unreachable from the cloud. Insist on a publicly routable SIP host — this is how the trunk Telemach inherited from Optima is built.
2. The username and password were issued but the trunk does not come up. Croatian operators do not publish parameters, and an e-mail easily leaves something out: clarify the exact address ("domena linije"), the port, the transport and whether registration from your PBX's address is allowed. Checking the address and port is covered by "Verify the link".
3. Outgoing calls go out with no number or with someone else's. The Croatian guide built the caller number on the P-Asserted-Identity header, while the PBX puts the number in From. Ask the operator to take the number from From.
4. A1 blocks calls or substitutes another number. The "Broj A" rule fired: the number is outside the contract range or the numbering area does not match the connection address. Check which behaviour was chosen in the order — the "block" option also disables 112.
5. The call connects but there is silence. Only G.729 was agreed on the trunk, and the PBX does not support it. Ask for G.711 a-law — it is the mandatory codec of the Croatian fixed network and everyone has it.
6. Two numbers land on the same line. The last seven digits of a Croatian number do not include the county code, so numbers from different areas can share a tail. Separate such lines manually.
7. 112 cannot be dialled. Emergency numbers shorter than four digits are not picked up by the catch-all outbound rule — create dedicated rules with an explicit pattern for them.

Country-independent causes are in "If calls do not go through", together with the SIP trace in the trunk menu. Transport and codec requirements are in "Network and compatibility".

Frequently asked questions#

Which provider should I choose if nothing is connected yet?#

TOP VoIP: the only public trunk price list in the country, free testing and an explicit promise that the trunk works over any internet connection and that you need not change your current operator. On a test account you can capture the real parameters and verify the setup within a day. Alternatives of the same kind are Signum/Telefonika and SKVID.

I already have a number with A1 or Telemach. Will it work with a cloud PBX?#

Most likely yes, but with a caveat to clear before signing: their trunk is historically delivered over the operator's own access line, and in the archived Optima guide the server address was private. The first question for the engineer is "which public SIP host and port will you provide, and is an ordinary internet connection enough". If the answer is not "a public address", take a second number from one of the providers with cards above.

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

For a local operator — yes: the contract is signed with a company or a sole trader holding an OIB, and a private individual will not be sold a business trunk. A foreign company without a Croatian registration will find it easier to take a +385 number from an international provider, where the requirement comes down to an address in the number's area and company documents.

Can I present a different number in outgoing calls?#

No. False presentation of the caller is banned by law (ZEK art. 48), and A1 enforces it technically: a number outside the contract range is either replaced by the Glavni broj or the call is blocked. Put only the numbers of your own contract in the "Present as" field.

How many channels should I order?#

A channel is one simultaneous conversation. A venue usually needs 2–4: one is taken by a guest, another by a courier or a supplier. Note that TOP VoIP offers 5 channels in the entry package and 15 in the larger one, while Tehnoline advertises up to 100 concurrent calls; with the carriers the number of channels is agreed in the order.

Will calls to 112 work over the trunk?#

With a local operator — yes, it is their legal obligation, but the site address for each number must be current on their side: the emergency call is routed by it. With A1 check separately that the "substitute the Glavni broj" option was chosen for invalid caller numbers rather than "block": blocking disables emergency calls too. With international providers 112 is a separate service and is not always available.

Sources#

All links checked on 09.09.2026.

Operators

• A1 Hrvatska — Biz IP Trunking: https://www.a1.hr/poslovni/govorne-usluge/biz-ip-trunking
• A1 Hrvatska — Uvjeti korištenja usluge Biz IP Trunking (PDF): https://ssc.a1.hr/documents/10307706/46744434/Uvjeti+kori%C5%A1tenja+usluge+Biz+IP+Trunking.pdf/847d98df-700b-c9df-1008-851d62096b06?t=1537861021604
• A1 Hrvatska — Uvjeti IP međupovezivanja (PDF, network transport and codecs): https://ssc.a1.hr/documents/10307706/1414102737/Uvjeti+IP+me%C4%91upovezivanja.pdf
• Telemach Hrvatska — Business Trunking: https://telemach.hr/poslovni/poslovna-rjesenja/poslovna-komunikacija/internet-telefon-i-podatkovne-usluge/business-trunking
• Optima Telekom — Upute za podešavanje Asterisk VoIP centrale (PDF, archived 22 Sep 2019): https://web.archive.org/web/20190922015537/https://www.optima.hr/system/document/pdf/206/Upute_za_podesavanje_Asterisk_VoIP_centrale.pdf
• Hrvatski Telekom — Cjenik za javne govorne usluge u nepokretnoj mreži za poslovne korisnike (PDF): https://www.hrvatskitelekom.hr/ResourceManager/FileDownload.aspx?rId=1225&rType=2
• Hrvatski Telekom — Specifikacija usluga: Net Phone paketi (PDF): https://www.hrvatskitelekom.hr/ResourceManager/FileDownload.aspx?rId=910&rType=2
• TOP VoIP — SIP trunk, packages and prices: https://topvoip.hr/voip-telefonske-usluge/sip-trunk/
• Signum telekomunikacije — SIP Trunking: https://signumtel.hr/sip-trunking/
• Telefonika — Cloud PBX and FAQ: https://telefonika.hr/index.php/cloudpbx/
• SKVID — Govorni kanali: SIP & IAX trunking: https://www.skvid.hr/hr/govorni-kanali
• SoftNET — SIP trunking: https://www.softnet.hr/SIP_trunking_2/
• Tehnoline Telekom — Cloud PBX / TehnoTel: https://tehnoline-telekom.hr/poslovni-korisnici-cloud-pbx/
• Fibernet — business offer: https://fibernet.hr/ponuda-poslovni-korisnici/
• Telnyx — Croatia DID requirements: https://support.telnyx.com/en/articles/3506141-croatia-did-requirements
• DIDWW — Croatia local numbers: https://www.didww.com/phone-numbers/local-numbers/Croatia/Local
• Zadarma — Croatian numbers: https://zadarma.com/en/tariffs/numbers/croatia/

Regulator and numbering

• Plan numeriranja, NN 45/2023: https://narodne-novine.nn.hr/clanci/sluzbeni/2023_04_45_783.html
• Zakon o elektroničkim komunikacijama (NN 76/22, consolidated text): https://www.zakon.hr/z/182/Zakon-o-elektroni%C4%8Dkim-komunikacijama
• HAKOM — adresni i brojevni prostor: https://www.hakom.hr/hr/adresni-i-brojevni-prostor/166
• data.gov.hr — register of primary numbering allocations to operators: https://data.gov.hr/ckan/dataset/popis-primarne-dodjele-numeracija-operatora-elektronickih-komunikacija

Related pages#

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