Name Business Trunking and its selected flavour
Proximus presents Enterprise Voice and Business Trunking as separate SIP-trunk services. The current Business Trunking service description defines Multi Standard, Multi Converged, Cloud Basic and Cloud Advanced, each with different included, optional or separately contracted elements.
Record the exact order, flavour, sites, implementation date and governing document before reusing any setting. A Proximus VoIP label does not make Enterprise Voice, Fixed Voice Infinity, Service Line Pro or Business Trunking interchangeable.
Documented service facts
Reviewed 2026-10-25. Compare SIP trunk services →
SIP authentication
Not verifiedThe reviewed public records define access, SBC and PBX responsibility but do not publish one universal credential profile. The selected implementation documentation and loaded configuration govern.
SIP registration
Not verifiedThe service description discusses cloud SBC voice and optional device registrations for named flavours. It does not establish one registration model for every Business Trunking order.
Inbound delivery and identity
DocumentedBusiness Trunking provides fixed numbers and public telephony access. Allocation, implementation, acceptance, routing, provider attempt, delivered identity and completed call remain separate.
Redundancy options
DocumentedThe CSD names Basic-Single, Single, Basic-Multi and Secure-Multi. Selected mode, path independence, trigger, alternate call and restoration remain unverified.
Countries and access
Not verifiedThe current product page describes Belgian and foreign numbers and multi-country availability. Site eligibility, Explore connectivity, data-centre reachability and lead time require dated qualification.
Codecs, DTMF and RTP
DocumentedThe CSD lists G.711, G.729, T.38 and DTMF. Offer and answer, packetization, RTP tuples and decoded media require current configuration and observation.
Fax
DocumentedThe CSD recommends T.38 when it can be ensured end to end and requires fallback because not every destination uses it. Negotiation and completed pages remain unverified.
Access and SBC boundary
Not verifiedThe selected flavour, Proximus connectivity, network SBC, customer or cloud SBC, PBX and contract determine the boundary. No universal TLS, SRTP or firewall profile was established by the reviewed public records.
Channels and call load
DocumentedThe trunk is dimensioned from customer data including requested channels. Ordered quantity, accepted configuration, current counters and completed simultaneous calls remain separate.
Emergency routing
DocumentedThe CSD defines site, number, remote-use, EVN and non-Belgian location conditions. Effective location, blocking, callback and approved test results remain unverified.
Pricing and contract
Not verifiedThe 1 January 2026 contract summary contains time-sensitive reference prices and says prices may change. The current quote, order, term, channels, numbers, options, usage and taxes govern.
Acceptance and support
DocumentedThe CSD defines implementation acceptance, service-desk and incident processes; the support page provides current contact routes. Selected coverage and observed response remain unverified.
SMS and MMS
Not verifiedThe reviewed Business Trunking records do not establish SMS or MMS entitlement, sender registration, API, throughput, webhook security, retention or price for trunk numbers.
Bind access, CPE, SBC and PBX responsibility
Multi Standard includes a voice-only physical access, data connectivity and data CPE. Multi Converged uses separately contracted Proximus data connectivity for voice and other traffic with managed voice capacity. Cloud Basic requires a separately contracted cloud SBC, while Cloud Advanced includes the cloud SBC.
The PBX and most customer-side components remain separate boundaries. Preserve access owner, CPE, demarcation, SBC management, PBX version and support scope instead of treating one reachable address as end-to-end service proof.
Keep numbers, channels and acceptance distinct
Business Trunking supplies fixed numbers, voice channels and public telephony access. The service description says Proximus dimensions the SIP trunk from the data-capture information, including requested channels, calling numbers, end users and codec.
An ordered channel count is not observed free capacity, and an allocated number is not a proven route. Keep request, order, implementation, acceptance, activation, provider attempt, PBX receipt and completed call as separate states.
Verify redundancy at both network and customer edges
The service description names Basic-Single as the default two-network-SBC design and also describes Single, Basic-Multi and Secure-Multi choices. These labels do not establish the selected design, customer-side diversity or a completed alternate call.
For an approved exercise, record network SBC targets, customer PBX or SBC legs, access paths, health evidence, first failed component, selected alternate, a completed new call and demonstrated restoration to the intended primary.
Separate codec, fax, signaling and media evidence
The service description lists G.711, G.729 and T.38 and recommends T.38 for fax when it can be ensured end to end, with fallback needed because not every destination uses T.38. These are capabilities and design inputs, not observed negotiation or completed-media proof.
Preserve offer and answer, packetization, DTMF, RTP tuples, packet direction, decoding, audible media, fax negotiation and delivered pages independently for the one attempt.
Treat emergency, price and support as order-bound
The service description imposes location and number conditions for remote, nomadic and non-Belgian use and warns that correct localization may not be possible in some designs. Do not place an uncoordinated emergency call. Verify location, presented identity, callback and alternate method through an approved process.
The 1 January 2026 summary is time-sensitive pre-contract information rather than a price promise. Current order, tariff, term, options, legal documents, service desk and escalation record govern the selected deployment.
Sources & applicability
Primary references for the technical details above. Operational examples and planning checklists are VoIP.info editorial guidance.
- Proximus — Business Trunking product overview ↗
- Proximus — Business Trunking contractual service description, 15 January 2024 ↗
- Proximus — Business Trunking contract summary, 1 January 2026 ↗
- Proximus — Professional-customer legal documents ↗
- Proximus — Customer service for large organisations ↗
Examples require adaptation to your topology. No live PBX or hardware testing is claimed.