Switzerland: 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 fill in the form, network requirements and how to test the connection. Here are the Swiss 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 documentation, regulator (BAKOM/OFCOM) materials and the Swiss telecommunications act (FMG); the links are in the "Sources" section.

In brief#

• You can buy a number with a SIP trunk in Switzerland, and your venue needs no licence for it. Under art. 4 FMG, BAKOM registers whoever uses radio frequencies subject to a concession or nationally managed numbers — that is your operator, not you.
• Four operators publish their server address and mode, and all four work in registration (REGISTER) mode: sipcall, peoplefone (CH), iWay and VTX. You can connect without calling a sales manager first.
• If no operator has been chosen yet, take sipcall. It publishes a ready Asterisk configuration with exactly our codecs (G.722, a-law, u-law), the number of concurrent channels is unlimited, no static IP is required on our side, and your internet provider can be any. The fallbacks are peoplefone (CH) and iWay.
• The main local pitfall is that the large operators are closed to a cloud PBX. Two of Swisscom's three products terminate on the operator's own box (an eSBC) inside the customer's network, and the third — the internet trunk — is documented as available only with TLS encryption, which our trunks do not support. The Sunrise trunk runs over Sunrise's own access. This market is held by mid-sized operators.
• The second pitfall is displaying someone else's number. Since 1 January 2026 (landline numbers) and 1 July 2026 (mobile numbers) Swiss operators must mark and anonymise calls that arrive from abroad with a Swiss number. Displaying your own number at local operators is possible, but it is an application-based service (CLI OPEN at peoplefone, Special Arrangement at VTX).
• The third pitfall is that emergency calls are tied to an address. sipcall requires a separate trunk for every site, peoplefone — a contact with an address for every line and number (the address is checked against the Swiss Road Directory). A single trunk for a chain of venues means a wrong address when someone calls 144.

Numbers in the country#

• The country code is +41. The national number has 9 digits, of which the first two are the area code (NDC) without the leading zero: 044 123 45 67.
• Geographic area codes: 21 Lausanne, 22 Geneva, 24 Yverdon, 26 Fribourg, 27 Sion, 31 Bern, 32 Biel and Neuchâtel, 33 Thun, 34 Burgdorf, 41 Lucerne, 43 and 44 Zurich, 52 Winterthur, 55 Rapperswil, 56 Baden, 61 Basel, 62 Olten, 71 St. Gallen, 81 Chur, 91 Lugano.
• Mobile numbers are 075…079, corporate networks 058, toll-free for the caller 0800, shared cost 0848, premium rate 0900, 0901, 0906.
• A direct-dial (Durchwahl) block does not make numbers longer. Under the numbering plan every number in a block has the same length as an ordinary one — appending digits is not allowed. A block looks like 044 123 45 60 … 044 123 45 69.
• Emergency numbers are 112 (general), 117 police, 118 fire, 144 ambulance, dialled without an area code.

On the "Lines" tab a number can be entered in any form: the PBX compares the last seven digits. ⚠️ In Switzerland a nine-digit number is 2 digits of area code plus 7 digits of the subscriber part, so those seven digits are the entire subscriber part without the area code. Numbers from different areas with the same tail (044 123 45 67 and 061 123 45 67) will collide on the lines; a Durchwahl block, on the contrary, is distinguished normally. If your numbers come from different cities, check the routing of every line by hand — "Add the number and routing".

Who issues a number with a SIP trunk#

The first four rows are operators whose trunk parameters are in public documentation: their cards are below. The rest hand out the server address, login and password only after a contract — they have a separate section.

sipcall (Backbone Solutions AG)#

A Swiss VoIP operator with the clearest documentation in the country: it has a knowledge base page specifically for Asterisk (PJSIP) and a separate one with its network addresses and ports. The trunk is a single registration of a "main number" to which the other numbers are attached; the number of concurrent channels is unlimited, no static IP is required ("registration is done via username and password, so the connection is dynamic"), and your internet provider can be any. Signing up is free and test numbers are issued immediately.

What to enter in the admin panel

What to set up at the provider: open an account at sipcall.ch → buy or port a number and choose the sip trunk product → in the control panel open the number → "SIP-Data" and write down the SIP Server, User id and VoIP password → attach the remaining numbers to the trunk's main number → set up a separate trunk for every physical site (the emergency address is tied to the main number).

Pitfalls ⚠️ The operator does not put your number into the address of the incoming call: in its own Asterisk example the number is taken from the To service header, while the address carries the trunk's User id. That means lines for different numbers cannot be told apart on this trunk — the call is still accepted and goes into routing as "a call from this provider", see "The provider sends its login instead of the number". Keep the routing common to the trunk. The operator does not recommend registering one account from several devices at once: one line, one device. The platform codecs are G.722, G.711 a-law, G.711 µ-law and others, and its own Asterisk example uses exactly our set; DTMF is RFC 2833, as with us. Source: sipcall KB, Asterisk PJSIP, networks and ports, the SIP-Trunk product — 09.09.2026.

peoplefone (CH)#

The same brand as in the German guide, but the Swiss account and numbers are separate: a Swiss account is also what makes local emergency services work. The trunk is a "SIP line" whose profile type is set to SIP-TRUNK; switching the type is free and is done in the control panel or by a partner. Since 2026 there is also a separate Domain-Based SIP-TRUNK product — an FQDN trunk with a login and password, billed per channel.

What to enter in the admin panel

What to set up at the provider: open a Swiss account → buy or port the numbers → set "Profil Typ = SIP-TRUNK" on the line you need → assign the number block to it → set the "angezeigte Rufnummer" (the number shown on outgoing calls) → submit the CLI OPEN form if required → create an emergency contact for every address.

Pitfalls ⚠️ Without the "SIP-TRUNK" profile type the line behaves as a single phone and does not send the headers needed for per-number routing — incoming calls arrive, but the lines cannot be told apart. If the number you display is still hosted at Swisscom, you must enable "Meine Nummer für Drittanbieter aktivieren" in the Swisscom portal, otherwise the call goes out anonymous. The incoming number arrives in E.164 or in the national format (+41445522000 or 0445522000) — both are parsed the same way. The publicly confirmed codecs are G.711 a-law and G.711 µ-law, which is enough for us; DTMF is RFC 2833. The operator sends NAT keepalives itself every 30 seconds, so no port forwarding is needed. Source: peoplefone (CH), SIP TRUNK, required firewall rules — 09.09.2026.

iWay#

A Zurich internet provider with its own telephony and a public wiki where the Asterisk registration string is spelled out literally — a rarity for the Swiss market. The product is called iWay SIP-Trunk; a "main number" (Hauptnummer) and a number block are attached to the trunk.

What to enter in the admin panel

What to set up at the provider: order an iWay SIP-Trunk → receive the sipuser, sippassword and Hauptnummer → attach the number block to the trunk; porting goes through the Portierungsformular on the operator's site.

Pitfalls ⚠️ A second infrastructure address — sip01.iway.ch — also appears in the operator's documents, and a new contract may well name that one, so enter the host the operator gave you rather than the one you found on the internet. The port, the transport and the codec list are not published in the wiki: if there is no registration after saving, or the call is silent, ask support about the port, the transport and enabling G.711 — "What to ask the provider". The incoming number arrives in the national format with a leading zero, so the line is matched by the last seven digits unambiguously. Source: the iWay wiki, Telefonanlage: Asterisk, the SIP-Trunk product — 09.09.2026.

VTX Services SA#

An operator from the French-speaking part of the country (Lausanne) with a public wiki that spells out the trunk parameters for a third-party PBX. The number of channels is set by the plan (Connect_PABX_4, _8, _60 and up), and the customer collects the credentials themselves in the VTX Kiosk portal.

What to enter in the admin panel

What to set up at the provider: order a Connect_PABX plan for the number of channels you need → collect the registrar, the Authentication ID and the password in the VTX Kiosk → ask for the incoming number format +E.164 or national (by default the operator sends the international form such as 0041215668340) → order a "Special Arrangement" if you need to display your own number on outgoing calls.

Pitfalls ⚠️ The server address is individual per customer — there is no shared VTX host you could take from a guide. The trunk codecs are G.722, G.711 a-law, G.729; our set matches on the first two. At this operator the P-Preferred-Identity header selects the billed number rather than the displayed one, and by default it should not be sent at all — our PBX does not send it, so this happens to match. The 0041… incoming format is parsed too: the seven-digit tail is found in it as well. Source: the public VTX wiki, trunk configuration — 09.09.2026.

Swisscom and Sunrise: why the large operators will not do#

The two largest operators in the country do sell SIP trunks, but none of the variants suits a PBX in the cloud.

Swisscom. The Smart Business Connect Trunk product terminates on an eSBC — a Cisco router the operator installs inside the customer's network: the registrar and proxy for the PBX is the address of that box, unreachable from the cloud (the older ConnectBox variant additionally uses port 5062 and only G.711 codecs). Enterprise SIP is the same plus a connection over the operator's own network, and there is no registration there at all. The third product, the SBCon Internet Trunk, does work over the internet and with registration, but it is documented as available exclusively with encryption enabled (TLS plus importing a root certificate), and our trunks do not support TLS — that combination will not work. Should Swisscom confirm an unencrypted mode for this product, the parameters (the registrar from the contract, the Authentifizierungs-ID and the password) go into the same form; note that a six-digit Kundendomänen-ID is mandatory there as the default outgoing number — without it outgoing calls do not go through at all.

Sunrise. The Business voice direct SIP-Trunk product is described by the operator itself as running "via Sunrise Access" — that is, over its own internet access and through its SBC, from four channels up; authorisation is by the public IP address of the PBX, the proxy is communicated individually, and the common codecs are only G.711 a-law and G.711 µ-law. The newer Business Voice IP PBX already uses registration and delivers the incoming number in +E.164. Technically the second variant would suit us, but both are sold together with Sunrise access, so for a machine in someone else's cloud they most likely will not be sold at all — check with the operator before signing.

Contract-only operators: Nexphone, Netvoip, Quickline and others#

These operators do have a SIP trunk and all of them work in registration mode, but the server address, login and password are issued only after a contract — there can be no "what to enter" table here. Ask the sales manager for the parameters using the list in "What to ask the provider" and enter them into the same form as for the others.

• Nexphone (Basel), the NX Business Trunk product — registration with a UserID and password, incoming number in the national format. Third-party tests found only one codec in common with us, G.711 a-law; that is exactly our set, but with no margin, so ask them to enable G.711 µ-law as well. They ask for T.38 fax to be switched off.
• Netvoip (Lucerne) — registration, incoming number in the national format, codecs G.711 a-law and G.711 µ-law. The host and port come from the control panel.
• Quickline — an alliance of cable operators; their page promises to connect your IP PBX "directly and without additional hardware", but to your own Quickline internet access. For a PBX in the cloud that is a limitation — ask outright whether they will sell the trunk without their access. Codecs are G.711 a-law, G.711 µ-law, G.729.
• SolNet (Solothurn) — registration, codecs G.711 a-law, G.711 µ-law, G.722, G.729: the best set among the smaller operators after sipcall.
• Plusviereins — registration, incoming number in the international format without the "+", codecs G.722, G.711 a-law, G.711 µ-law, G.729.
• VoIP-One (Zurich) — ordering online, plans ranging from outgoing-only to packages by number count, an unlimited number of concurrent channels, and Asterisk compatibility claimed by the operator itself. The host, ports and codecs are not published on the site — they are issued after sign-up.
• Salt — we found no publicly sold trunk for a third-party PBX: their business bundle comes with their own router, and the description states plainly that SIP phones are not compatible with it. Trade press wrote about a trunking product from this operator, but there is no such page on its site — ask their sales department.

International providers with Swiss numbers#

International providers cover Switzerland more thinly than neighbouring Germany, France and Italy, and with the strictest document checks in the region:

• DIDWW sells Swiss landline and toll-free numbers; mobile, national and shared-cost numbers are unavailable for this country.
• Twilio approves local landline numbers only for individuals residing in the corresponding region, with proof of identity and address; Swiss mobile numbers there have no voice at all — SMS only.
• The general address rule: the physical address must be within the locality the number's prefix covers, and a PO box is not accepted. Buying a Geneva +41 22 against an address in another country will not work.
• ⚠️ And above all, caller ID. Since 2026 Swiss operators mark and anonymise calls arriving from abroad with a Swiss number. The pattern "a Swiss number at an international provider, outgoing calls through it as well" risks showing "anonymous" to the person you call — test it on a live call before handing the number out to guests.

The parameters of the international providers themselves are in the catalogue shown when adding a provider: most of them already have a card there, and the server address and mode are filled in for you.

Number porting#

• Porting a number is a subscriber's right, established by the telecommunications act, and BAKOM keeps a dedicated section with porting rules. The request is filed by the receiving operator: at sipcall it is a form in the control panel, at iWay the Portierungsformular on the website.
• Timelines are not published by local operators. In practice porting between VoIP operators takes a few business days, while a number on the incumbent's copper line can take weeks.
• What breaks during porting: the emergency address (it has to be set up again at the new operator), the permission to display your own number (the CLI OPEN or Special Arrangement application is filed again), and the binding of the number to a line or trunk.
• A Durchwahl block is ported as a whole: the numbers in it may not be made longer or shorter.
• If the number stays at Swisscom while you want to display it through another operator, be sure to enable "Meine Nummer für Drittanbieter aktivieren" in the Swisscom portal — otherwise their filter will deliver the call as anonymous.

Rules and documents#

If it does not work#

1. "Not registered with the provider" while the login and password look right. Almost certainly the control panel password has been entered: at sipcall the SIP password is called "VoIP password" and lives in the SIP-Data card, at peoplefone it is individual per line and differs from the portal login.
2. The server address has been mixed up. At sipcall and VTX the host is individual per customer (the SIP-Data card and s1.<customer number>.trk.ipvoip.ch respectively) — no shared address from a guide exists. At iWay two addresses live in the documents, sip3.phone.iway.ch and sip01.iway.ch: use the one the operator named.
3. VTX: registration does not go through over UDP. The operator recommends TCP — set it in the "Transport" field and repeat the connection test.
4. Incoming calls arrive but lines are not matched by number. At sipcall the number is not placed into the call address — lines do not work on that trunk, so keep the routing common to the trunk. At peoplefone the cause is different: the line has not been switched to the "SIP-TRUNK" profile type, which is done in the control panel free of charge.
5. Calls to two numbers land on the same line. The last seven digits of numbers from different areas coincide (044 … and 061 …) — in Switzerland those seven digits are the whole subscriber part. Separate such lines by hand, or take numbers from one area and a Durchwahl block.
6. Swisscom or Sunrise: silence with no clear error. The Swisscom internet trunk is documented as working only with encryption, which we do not have, while the Sunrise trunk runs over the operator's own access and authorises by IP address. This is a product incompatibility rather than a setting — see the section above.
7. The call connects but there is silence — the codecs did not match: our PBX speaks G.711 and G.722. At iWay, Netvoip and VoIP-One the codec list is not publicly described — ask support to enable G.711. At Nexphone third-party tests found only one codec in common (G.711 a-law), with no margin.
8. The wrong number is displayed on outgoing calls. At local operators caller ID is configured on their side: at peoplefone it is CLI OPEN by a signed form plus the "angezeigte Rufnummer" set on the line, at VTX a "Special Arrangement". Until the service is enabled, the call goes out with the trunk's default number — "Outgoing calls".

Causes that do not depend on the country are in "If calls do not go through"; the SIP trace in the trunk menu is described there too.

FAQ#

Which operator should I choose if nothing has been connected yet?#

sipcall. It publishes a ready Asterisk configuration with exactly our codecs, the number of concurrent channels is unlimited, no static IP is required on our side, and the account is opened online within an hour. The only price for that is that lines for different numbers cannot be told apart on its trunk. If you have several numbers and need to route them into different scenarios, take peoplefone (CH) or iWay.

Can I get a Swiss number if the company is registered outside Switzerland?#

At a local operator — hardly: the contract is signed with a Swiss entity, and none of the operators we checked describes a public procedure for foreign companies. International providers do sell Swiss numbers, but they require proof of an address within the number's area, and Twilio requires a local individual for landline numbers altogether.

Why does Swisscom not suit?#

Two of its three products terminate on a router the operator installs in your network: the registrar for the PBX is the address of that box, which cannot be reached from the cloud. The third, the internet trunk, is documented as available only with TLS encryption enabled, and our PBX does not support TLS for trunks. This is a limitation of the product, not of the settings.

Can I display a different number on outgoing calls?#

Only another number of your own, and only with the service enabled at the operator: at peoplefone that is CLI OPEN by a signed form, at VTX a "Special Arrangement". And displaying a Swiss number while calling from abroad through an international provider has become practically impossible since 2026: Swiss operators mark and anonymise such calls at the border.

How many channels does a venue need?#

A channel is one concurrent conversation. A restaurant usually needs 2–3: one is busy with a guest, the second with a courier or a supplier. At sipcall and VoIP-One the number of channels is unlimited, at VTX it is set by the plan (Connect_PABX_4, _8, _60), and at Sunrise the minimum is four. "Calls stop going through after the third one" is a plan limit, not a fault.

We have several venues — can we use one trunk for all of them?#

Technically yes, but you should not: the emergency address is tied to a trunk or a line. sipcall explicitly requires a separate trunk for every site, even when the PBX is a single one, and peoplefone requires a contact with an address for every line and number. One trunk for a chain of venues means that a call to 144 will send help to the address of the first one.

Sources#

All links were checked on 09.09.2026.

Operators

• sipcall — Asterisk (PJSIP) setup, a complete configuration example: https://kb.sipcall.ch/en/enddevices/phonesystems/asterisk/
• sipcall — networks, ports and firewall rules: https://kb.sipcall.ch/en/technical/firewall_configuration
• sipcall — codecs: https://kb.sipcall.ch/en/technical/codecs · DTMF: https://kb.sipcall.ch/en/technical/dtmf
• sipcall — the SIP-Trunk product: https://www.sipcall.ch/loesungen/sipcall-sip-trunk/
• peoplefone (CH) — SIP TRUNK: https://support.peoplefone.com/che/peoplefone-produkte/peoplefone-sip-trunk/
• peoplefone (CH) — required firewall rules: https://support.peoplefone.com/ch/fehlerbehebung/benotigte-firewall-regeln/
• peoplefone — Domain-Based SIP-TRUNK: https://www.peoplefone.com/de-ch/kunden/produkte/telefonie/domain-based-sip-trunk
• iWay — wiki: connecting Asterisk: https://wiki.iway.ch/kb/wiki/VoIP_Telefonie/Konfigurationen/Telefonanlagen,_PBX/Telefonanlage:_Asterisk
• iWay — the SIP-Trunk product: https://www.iway.ch/business/telefonie/sip-trunk/
• VTX — public wiki, trunk configuration for a third-party PBX: https://wiki.vtx.ch/wiki/VoIP:Hardware:3CX:Configuration
• Swisscom — Smart Business Connect Trunk, connecting a PBX: https://documents.swisscom.com/product/1000614-Smart_Business_Connect/Documents/Technische_Dokumentation/pbx_anbindung_bintec_elmeg_smartbusinessconnect-de.pdf
• Swisscom — Enterprise SIP: https://www.swisscom.ch/en/business/enterprise/offer/wireline/enterprise-sip.html
• Sunrise — Business voice direct SIP-Trunk: https://www.sunrise.ch/content/dam/sunrise/business/telefonie/sip-trunk-business-voice-direct/produktinformation-sip-trunk-business-voice-direct.pdf
• Quickline — IP-Telefonanlagen: https://quickline.ch/business/festnetz/ip-telefonanlagen
• VoIP-One — SIP-Telefonanschlüsse: https://www.voipone.ch/sip-telefonanschluesse/
• Salt — Pro Business Telephony: https://www.salt.ch/en/business/internet-fixnet/telephony
• DIDWW — Swiss phone numbers: https://www.didww.com/phone-numbers/all-phone-numbers/Switzerland/Local
• Twilio — Switzerland regulatory guidelines: https://www.twilio.com/en-us/guidelines/ch/regulatory

Regulator and law

• Fernmeldegesetz (FMG, SR 784.10): https://www.fedlex.admin.ch/filestore/fedlex.data.admin.ch/eli/cc/1997/2187_2187_2187/20230901/de/pdf-a/fedlex-data-admin-ch-eli-cc-1997-2187_2187_2187-20230901-de-pdf-a.pdf
• BAKOM — the E.164 numbering plan (number length, area codes, service ranges): https://www.bakom.admin.ch/dam/de/sd-web/Z0P7gateTOUQ/Def_zur_Sig_TAV_PTA_-_2.2_-_Edition8_-_d.pdf
• BAKOM — allocation of number blocks and withdrawal conditions: https://www.egov.swiss/nummernbloecke/E164-Information-DE-20210101.pdf
• BAKOM — identification of the calling line (marking calls from abroad): https://www.bakom.admin.ch/de/identifikation-des-anrufenden-anschlusses
• BAKOM — numbering and telephony, number porting: https://www.bakom.admin.ch/de/nummerierung-telefonie

Related pages#

• Connecting a provider's number to the PBX — the common steps, trunk modes, network, connection test.
• Setting up SIP phones — how to connect desk phones and DECT to extensions.
• Germany: SIP providers and connecting a number — the neighbouring market and the second peoplefone account.