SIP Trunk in Italy — Rome, Milan or Naples Inbound + Outbound

1. What a SIP trunk in Italy actually is

A SIP trunk is the IP delivery pipe between a carrier and your PBX, AI voice agent, or call-control platform; signaling over SIP, audio over RTP. A Italy SIP trunk is the same thing carrying +39 Italy DIDs allocated under AGCOM.

DIDHub provides the trunk authentication and SIP transport; AGCOM-compliant number allocation is coordinated through our in-region carrier partners. Your PBX or platform sees a standard SIP trunk; we handle the regulator-side paperwork.

2. Italy regulation: AGCOM, KYC, compliance

AGCOM doesn't require KYC for standard Italy number allocation. Activation is Instant.

What people typically use a Italy SIP trunk for:

• Italian market entry, Italian buyers strongly prefer Italian Caller IDs.
• Milan business presence with 02 for fashion, finance, B2B.
• Rome government / institutional with 06.
• National 199 for premium-rate service lines.
• Toll-free 800, free for Italian callers.

Italy is one of the easier EU countries for virtual phone number allocation. AGCOM does not require KYC for standard geographic, 178/179 VoIP, or 800 toll-free numbers. Activation is instant.

For the broader picture across countries, see our guide to international DID compliance & KYC bundles. For the SIP-trunk concept end-to-end, see the DID Number Provider guide.

3. Number types you can route over the trunk

DIDHub supports the standard Italy number types over the SIP trunk:

For a deeper look at how number types differ globally, see DID number types explained.

4. How DIDHub's SIP trunk works in Italy

The technical surface of the trunk is standardised; the Italy-specific choices are the POP, the codec list, and the failover topology.

Ingress POPs

• Frankfurt (primary), lowest in-region latency to Italy endpoints.
• London (failover), secondary route used if the primary path degrades.

Transport & security

• TLS:5061 recommended for any production trunk; UDP allowed for legacy.
• SRTP for media via DTLS-SRTP or SDES.
• SIP authentication: digest registration (PBX behind NAT) or IP-ACL (static peering). See SIP authentication.

Codecs

• G.711 a-law (PCMA), the European default.
• G.722, wideband HD voice on capable endpoints.
• Opus, for AI voice agents and IP-native softphones.
• G.729, available on request.

For the codec deep-dive, see voice codecs explained.

DTMF

• RFC 4733 (telephone-events over RTP) is the default. SIP INFO and in-band DTMF available for legacy interop on request.

Channel concurrency

• Trunks start at 5 concurrent channels and scale to 200 per trunk off the shelf. Larger requires a custom arrangement.
• Channels are independent of DID count; you can carry 200 numbers on a 10-channel trunk if your concurrent-call peak is 10. See multiple concurrent calls on one DID.

STIR/SHAKEN

• Not applicable. The North-American STIR/SHAKEN attestation framework is a US/Canada construct that doesn't exist in Europe. EU trust signals come through national regulator registration and operator-side caller-ID validation.

5. Outbound calling from your Italy trunk

Outbound from a Italy-allocated DID to Italy destinations is allowed within approved use cases. The per-minute economics:

Outbound caller-ID rules

• Your outbound CLI must match a DID you've allocated through the trunk. Setting an arbitrary caller ID is rejected at the SBC.
• Origin-based rating (OBR) applies on cross-border outbound, the regulated EEA tier may apply depending on the source carrier.
• For multi-region operators, see origin-based rating savings.

6. Setup in 6 steps

Asterisk pjsip example

; /etc/asterisk/pjsip.conf
[transport-tls]
type=transport
protocol=tls
bind=0.0.0.0:5061
cert_file=/etc/asterisk/keys/asterisk.crt
priv_key_file=/etc/asterisk/keys/asterisk.key
method=tlsv1_2

[didhub-italy]
type=auth
auth_type=userpass
username=YOUR_DIDHUB_USERNAME
password=YOUR_DIDHUB_PASSWORD

[didhub-italy]
type=aor
contact=sip:sip.didhub.io:5061;transport=tls
qualify_frequency=30

[didhub-italy]
type=endpoint
transport=transport-tls
context=from-didhub
disallow=all
allow=g711a,g722,opus
outbound_auth=didhub-italy
aors=didhub-italy
dtmf_mode=rfc4733
media_encryption=sdes
direct_media=no

3CX SIP trunk template snapshot

# 3CX -> SIP Trunks -> Add SIP Trunk -> Generic SIP Trunk
Trunk name:        DIDHub Italy
Registrar:         sip.didhub.io
Transport:         TLS
Port:              5061
Authentication:    Register/Account based
Auth ID:           YOUR_DIDHUB_USERNAME
Auth password:     YOUR_DIDHUB_PASSWORD
Outbound caller ID: +39 ... (one of your allocated DIDs)
Codecs (priority):  G.711a / G.722 / Opus

7. Integration patterns

Every modern PBX, UC platform, and AI voice stack can authenticate against the trunk:

8. Pricing

Four line items: per-DID monthly rental, per-minute inbound usage on every Italy DID (even landline geographic numbers carry an inbound MOU charge in Italy), channel capacity, and per-minute outbound. Setup is $0 once AGCOM paperwork is approved.

Per-DID monthly

Channel capacity

Per-minute outbound

See section 5 above and the full global rate sheet.

9. Porting an existing Italy number

Existing Italy number? Porting timeline is 2-4 weeks.

• Typical port time: 2-4 weeks
• Required documents: phone bill + LOA + ID + proof of address (AGCOM requirements)
• Cost: port-in fee per number; carrier-side fees may apply

For the full porting playbook (US/UK/EU + the global gotchas), see number porting explained.

10. FAQ

Which POP should I connect to for a Italy SIP trunk?

Frankfurt is the recommended primary; London is the standard failover. Both terminate to Italy via in-region carriers.

How long does activation take for a Italy SIP trunk?

Instant after KYC documents are accepted (or instantly where KYC isn't required). Provisioning the SIP side itself is hours, not days; the variability is on the AGCOM/carrier side.

What codecs should I configure for a Italy SIP trunk?

G.711a / G.722 / Opus as the negotiation list, in that order. G.711a is the regional default for Italy interop.

Can I use my Italy SIP trunk with Microsoft Teams?

Yes, via Microsoft Teams Direct Routing through DIDHub's managed SBC. See Teams Direct Routing.

Can I use my Italy SIP trunk with AI voice agents (Vapi, Retell, ElevenLabs)?

Yes, BYOC SIP trunk works with every major AI voice platform. Bind specific Italy DIDs to specific agents; outbound CLI must match an allocated DID.

How many concurrent calls can one Italy DID handle?

The DID is an address; concurrent-call capacity is set by the channel count on the trunk. A 50-channel trunk with 1 DID can carry 50 concurrent calls to that one number; the same trunk with 200 DIDs can carry 50 concurrent calls across any combination of those numbers.

Does STIR/SHAKEN apply in Italy?

N/A (regional construct). Trust signals come instead through national regulator registration and operator-side caller-ID validation.

Can I port my existing Italy number to a DIDHub SIP trunk?

Yes. Typical Italy port timeline is 2-4 weeks. Required documents vary by number type; contact us for the specific checklist. See number porting explained for the global picture.

What use cases get approved most easily?

Customer service inbound, opted-in callbacks, transactional 2FA, inbound AI voice agents, and Microsoft Teams Direct Routing for registered entities. Cold outbound, unsolicited SMS campaigns, and anonymous-relay setups are routinely rejected.

11. Related country pages