Keep the PBX trunk distinct from adjacent Fusion services
Fusion Connect describes SIP Trunks for an existing IP PBX and separately markets Hosted Voice, Unified Communications, Microsoft Teams Calling, Business Texting, Hosted Fax, analog and PRI services. These offers can share provider infrastructure without sharing the same customer handoff, feature entitlement or commercial terms.
Record the exact SIP Trunks product, customer site, access, provider equipment, PBX or SBC, number inventory, calling plan and signed options. Do not import messaging, fax, continuity or collaboration features from an adjacent product merely because the portfolio uses SIP or the same provider.
Documented service facts
Reviewed 2026-10-07. Compare SIP trunk services →
SIP authentication
DocumentedFusion Connect says call initiation requires both SIP credentials and a customer-assigned specific IP address. That documents a two-condition provider policy, not certificate-based mutual TLS, universal source ranges or proof that an observed request was authorized. Preserve the issued credential object, accepted source address, NAT or SBC ownership and provider confirmation for the exact trunk.
SIP registration
Not verifiedThe product page says company registration is locked to a specific IP address, but the reviewed public materials do not define one REGISTER, static-peer, refresh, realm, outbound-proxy or failover-registration workflow for every order. Use the provider-issued implementation record rather than converting marketing wording into a universal SIP configuration.
Inbound delivery
DocumentedFusion Connect describes a PBX-facing PSTN service, unlimited DID support and a Business Telephone Number included with each order. That establishes service and ordering roles, not unlimited assigned inventory or one Request-URI, P-Asserted-Identity, Diversion, number-format or PBX-destination rule. Capture the provisioned numbers and delivered identifiers for the actual order.
Routing and failover
DocumentedOptional hosted Auto Attendant, Voicemail and Call Forwarding are advertised for continuity when the PBX or office is unavailable. The service guarantee applies to underlying infrastructure, and neither statement proves that one order includes an alternate destination, diverse customer access or established-call survival. Confirm signed options and test approved new-call failures separately.
Number and regional availability
Not verifiedThe calling plan advertises domestic calling to the United States and Canada and DID support, while service guarantees name several countries for selected terms. These claims do not establish customer eligibility, serviceability, number inventory, port eligibility or regulatory approval for a particular address. Use dated serviceability and port responses.
Audio codecs
Not verifiedThe reviewed public product, solution-sheet, PBX-list and guarantee materials do not publish one universal codec, packetization, DTMF, RTP-addressing or transcoding profile. Obtain the current interface specification and preserve the actual SDP offer, answer, RTP path and decoded audio for every PBX-facing leg.
T.38 fax
Not verifiedThe product page separately discusses analog and PRI services, but the reviewed SIP Trunks materials do not establish T.38 entitlement, G.711 pass-through requirements, gateway behavior, page profile or support for one fax path. Do not transfer analog, PRI or hosted-fax capabilities to the SIP trunk; validate the exact design and delivery report.
Signaling and media encryption
Not verifiedCredentials plus a specific source IP document call-initiation controls. They do not establish SIP TLS, certificate validation, SRTP, media encryption or downgrade policy. Private-cloud and prioritized-traffic language likewise does not prove application-layer protection or the customer access path. Obtain the current security specification and inspect each hop.
Concurrent calls and call starts
DocumentedFusion Connect prices the plan by required concurrent call sessions, publishes a minimum purchase of three sessions and offers optional Call Bursting above subscribed capacity. These are ordering constructs, not observed concurrent calls, a burst ceiling, calls-per-second tolerance, PBX or SBC resources, or access-bandwidth acceptance. Keep each quantity separate.
Emergency calling
DocumentedFusion Connect says each order includes a Business Telephone Number for E911 service location. That does not establish that the correct address, outbound identity, callback route, location update or provider-approved test has been accepted for a particular site. Preserve the signed emergency terms and validate each location through the permitted process.
Pricing model
DocumentedThe public page describes a flat monthly rate based on concurrent call sessions, a three-session minimum, included US and Canada calling, and optional continuity, calling-name and bursting features, but directs buyers to obtain a quote. Use a dated quote and signed schedule for usage scope, numbers, ports, access, equipment, add-ons, emergency service, taxes, support, renewal and cancellation.
Administration and support
Not verifiedFusion Connect advertises a consultative design, provider-supplied Router or IAD with selected voice services, interoperability confirmation before purchase and broad service guarantees. The reviewed sources do not establish one portal, change workflow, support tier, demarcation or response target for every SIP Trunks order. Preserve current contacts, acceptance criteria and signed guarantee terms.
SMS and MMS
Not verifiedA generic product FAQ mentions messaging and SMS when defining SIP service, while Fusion Connect lists Business Texting as a separate service. The reviewed SIP Trunks materials do not establish SMS or MMS entitlement on trunk DIDs, API access, sender registration, throughput, webhook security or price. Do not convert a protocol description into a trunk feature.
Treat credential and source IP as separate controls
Fusion Connect says call initiation requires SIP credentials and a customer-assigned specific IP address. Preserve the issued credential object and the accepted public source address, then identify any firewall, NAT, provider router or SBC that owns the address. A matching address does not prove a credential succeeded, and an accepted call does not establish TLS or media encryption.
The public wording about registration being locked to an IP address does not publish a universal REGISTER or static-peer recipe. Use the provider-issued implementation record for peers, realm, proxy, refresh behavior, transports and failover. Capture signaling evidence without exposing secrets.
Separate sessions, bursting and network capacity
The published plan uses concurrent call sessions, requires at least three purchased sessions and offers optional Call Bursting for peaks above subscribed capacity. Treat subscribed sessions, active calls, attempted call starts, burst allowance, PBX channels, SBC resources, codec bandwidth and access utilization as separate quantities. A commercial session count is not a measured calls-per-second or quality result.
The product page advertises prioritized voice traffic and provider-supplied Router or IAD options. Those claims do not establish the customer's last-mile design, end-to-end QoS, diverse access, a burst ceiling or capacity acceptance. Obtain the order and validate under an approved plan.
Convert DID, E911 and compatibility claims into records
Fusion Connect says SIP Trunks support unlimited DIDs and each order includes a BTN for E911 service location, outbound caller-name setup and directory-listing setup. Unlimited support does not mean unlimited provisioned inventory, ports, concurrent calls or included charges. Preserve the assigned BTN and DIDs, port state, authorized identities, emergency address, callback path and provider-approved test result for every site.
The provider's manufacturer page says listed PBX families have been deployed and names FreePBX among them. That is useful discovery evidence, not acceptance of every model, firmware, module, codec or configuration. Use exact versions and a current interoperability confirmation or demo result.
Purchase and test continuity explicitly
Fusion Connect advertises optional hosted Auto Attendant, Voicemail and Call Forwarding for continuity, plus an infrastructure service guarantee. Confirm which options, destinations, triggers, support boundaries, credits and exclusions are actually in the signed order. Provider-infrastructure uptime does not prove customer access, power, LAN, PBX or endpoint availability.
Document primary and alternate routing, retryable outcomes, timers, provider actions and restoration. Test approved new-call failures and keep established-call survival separate. The reviewed public materials do not establish a universal codec, DTMF, TLS, SRTP, T.38, SMS or MMS profile. No account, trunk, PBX, call, media, fax, protected path, burst, continuity, emergency workflow, message, availability, price or support response was inspected or tested for this guide.
Sources & applicability
Primary references for the technical details above. Operational examples and planning checklists are VoIP.info editorial guidance.
- Fusion Connect SIP Trunks ↗
- Fusion Connect SIP Trunking solution sheet ↗
- Fusion Connect IP-PBX devices and manufacturers ↗
- Fusion Connect service guarantees ↗
Examples require adaptation to your topology. No live PBX or hardware testing is claimed.