Enterprise & Business Voice
One managed voice service for every office and every country - SIP trunks, numbers, PSTN breakout and calling plans on a single platform, integrated with your PBX, Microsoft Teams or contact centre.
110+
Countries with numbers
600+
Carrier interconnects
1
Contract, platform and invoice
What is Enterprise & Business Voice?
Dollu Enterprise & Business Voice replaces the patchwork of national carriers, ISDN circuits and regional SIP providers that most multinational organisations have accumulated with a single, managed voice service. We provide the SIP trunks, the numbers, the outbound calling plans and the regulatory registrations in every country you operate, delivered from a geo-redundant core with PoPs in London, Frankfurt, Amsterdam, Ashburn, Mumbai and Singapore. You get one contract, one portal, one invoice and one number to call when something needs attention.
The service is built to sit behind whatever your teams already use. We connect to on-premises IP-PBXs from Cisco, Avaya, Mitel and Alcatel-Lucent Enterprise, to session border controllers from AudioCodes, Oracle and Ribbon, and natively to Microsoft Teams through Direct Routing and Operator Connect, to Zoom Phone and Webex Calling through their carrier programmes, and to leading contact-centre platforms over SIP. Hybrid estates - Teams in head office, a legacy PBX in the plant, a cloud contact centre for customer service - share the same trunks, numbers and dial plan.
Because we hold direct interconnects with more than 600 carriers and operate numbers in 110+ countries, we can consolidate country-by-country carrier relationships into one. Local, national and toll-free ranges are ported or provisioned per country, outbound calls break out to the PSTN through in-country or nearest-PoP routes with correct caller-ID presentation, and emergency calling is configured to the local rules. Where regulation requires a local entity, address proof or KYC documentation, our regulatory desk manages the paperwork and keeps it current so numbers are never suspended for a missing form.
Commercially the service is designed for finance teams as much as for IT. Calling plans can be bundled per user, per site or per country, or billed on metered wholesale rates with committed-volume discounts, in USD, EUR, GBP or INR. Compliance call recording, encrypted archiving and retention policies for regulated sectors are available as options, as are dedicated private interconnects, PCI-DSS pause-and-resume for payment lines and 24×7 NOC monitoring with a named account manager and quarterly service reviews.
SIP trunk topology: from your PBX to the PSTN.
Why choose Dollu for enterprise voice.
The advantages of buying from a carrier that owns its network, interconnects and operations - rather than a reseller.
Consolidate dozens of carriers into one
Retire the per-country contracts, invoices and escalation paths. One agreement covers trunks, numbers, porting and regulatory filings everywhere you operate.
Keep the platforms your teams already use
We integrate with your PBX, SBC, Teams tenant or contact-centre platform rather than replacing it, so migration is a trunk swap and a number port, not a re-platforming project.
Predictable, transparent cost
Bundled calling plans for budgeting certainty or metered wholesale rates for volume, with a single multi-currency invoice broken down by site, country and cost centre.
Compliance handled country by country
Number-usage rules, KYC, emergency-calling obligations and recording requirements differ everywhere. Our regulatory desk applies the right rules per country so you do not have to track them.
Enterprise-grade resilience
Geo-redundant registrars and media, dual-homed trunks to two PoPs, automatic failover to a secondary SBC or mobile numbers and a 99.99% core availability target.
Capabilities in detail.
Everything included with Enterprise & Business Voice - the platform features, options and controls you get from day one.
- 01
Global SIP trunking
Centralised or distributed trunks over internet, IPsec, MPLS or PoP cross-connect; TLS/SRTP; registration or static IP; per-trunk channel and CPS limits; local media breakout to keep latency low.
- 02
Numbers and porting in 110+ countries
Local, national, mobile and toll-free numbers, bulk porting managed by our porting desk with cut-over scheduling per country, and number inventory shared across all connected platforms.
- 03
UC and contact-centre integration
Microsoft Teams Direct Routing and Operator Connect, Zoom Phone Provider Exchange, Webex Calling Cloud Connect, Genesys, NICE, Five9 and Amazon Connect over SIP, plus certified SBC configuration guides.
- 04
Calling plans and rating
Domestic and international bundles per user or per site, pooled minutes across sites, metered wholesale rating with committed-volume tiers, and spend caps and alerts per department.
- 05
Compliance call recording
Network-side SIPREC recording with AES-256 encrypted storage, configurable retention, legal hold, PCI-DSS pause-and-resume and export to your archive or e-discovery platform.
- 06
Caller-ID and dial-plan management
Per-user and per-site outbound CLI policies, presentation rules per country, centralised dial-plan normalisation and short-code dialling between sites regardless of platform.
- 07
Emergency calling per country
E911 with dynamic location in the US and Canada, 112 and 999 routing internationally, address registration at provisioning and clear flags where a number type cannot carry emergency calls.
- 08
Managed service and reporting
24×7 NOC monitoring of trunks and registrations, call-quality dashboards per site, monthly service reports, a named account manager and quarterly reviews of usage, cost and roadmap.
How it works.
From first conversation to live traffic - a tracked, engineer-led onboarding with a named owner at every step.
- Step 01
Discover
We audit your sites, number ranges, existing carriers, PBX and SBC estate and contract end dates, and produce a country-by-country migration plan with savings and risk noted per site.
- Step 02
Design
Trunk topology, SBC or Teams configuration, dial plan, CLI policies, emergency-calling and recording requirements are agreed and documented; regulatory paperwork is started in parallel.
- Step 03
Migrate
Numbers are ported and sites cut over in waves, typically out of hours, with a rollback path per wave. Test plans cover inbound, outbound, emergency and fax before sign-off.
- Step 04
Operate
Your account manager and the 24×7 NOC take over. Adds, moves and changes are handled through the portal or API, and quarterly reviews keep cost and capacity aligned to the business.
SIP trunk vs ISDN PRI.
What changes when you move a PBX, contact centre or Teams estate from ISDN circuits to SIP - and why most estates never go back.
| Dimension | SIP trunkDollu recommends | ISDN PRI |
|---|---|---|
| Capacity per unit | Elastic - channels are added in software; burst capacity on demand for peaks | Fixed - 30 B-channels per E1 (23 per T1); a new circuit for every step up |
| Provisioning time | Hours to days over any existing IP connectivity | Weeks - physical circuit delivery, PBX card and installation visit |
| Resilience | Registration to multiple Dollu PoPs, DNS SRV failover, geographic redundancy without extra circuits | A single physical path unless a second circuit is installed and paid for |
| Media security | TLS signalling and SRTP media end to end; SBC-fronted | Physically separate circuit; no encryption in the protocol itself |
| Number portability | Numbers from 110+ countries on one trunk - ported in or newly issued; not tied to a location | Numbers tied to the local exchange and the circuit’s address; moving means porting |
| Cost model | Per channel or per concurrent call plus per-second usage; no circuit rental or install charge | Circuit rental plus per-channel plus per-minute usage; install and engineer charges |
| Future-proofing | Native to Teams Direct Routing, cloud PBX, CCaaS and voice APIs; ready for the ISDN switch-off | Being withdrawn - PSTN and ISDN switch-off programmes are under way in the UK, EU and elsewhere |
Who uses this and why.
Typical deployments across carriers, enterprises, platforms and contact centres.
Multinational head-office and branch estates
Standardise voice across dozens of countries with local numbers and PSTN breakout everywhere and one central policy for CLI, recording and emergency calling.
Microsoft Teams voice rollouts
Bring PSTN calling to Teams tenants worldwide with Direct Routing or Operator Connect, keeping existing numbers and phasing out legacy PBXs at your own pace.
Contact centres with global reach
Local inbound numbers in every market served, high-quality outbound with correct CLI and compliant recording feeding your CCaaS or on-premises platform.
Mergers, acquisitions and carve-outs
Absorb an acquired company’s numbers and trunks onto one platform quickly, or split an estate cleanly, without renegotiating a dozen carrier contracts.
Regulated industries
Banks, insurers, healthcare providers and law firms that need recording, retention, access controls and audit trails applied consistently across every office.
Technical & commercial specifications.
Key parameters at a glance. Ask us for the full service description and SLA document.
| Coverage | Numbers in 110+ countries; PSTN breakout worldwide |
|---|---|
| Integration | Teams Direct Routing/Operator Connect, Zoom, Webex, SIP PBX/SBC, CCaaS |
| Signalling | SIP over UDP/TCP/TLS; registration or static IP; SIP OPTIONS keep-alive |
| Media | RTP/SRTP; G.711, G.729, G.722, Opus; T.38 fax |
| Numbers | Local, national, mobile, toll-free; bulk porting per country |
| Calling plans | Per user, per site, pooled or metered; USD/EUR/GBP/INR |
| Recording | SIPREC; AES-256 storage; retention, legal hold, PCI pause/resume |
| Resilience | Geo-redundant core; dual-PoP trunks; 99.99% core availability |
| Support | 24×7 NOC; P1 response ≤ 15 min; named account manager; QBRs |
How Voice & Wholesale is priced.
Wholesale voice is priced from an A–Z rate deck: a rate per destination and breakout for each quality tier, billed on connected seconds. There are no setup or port fees on SIP interconnects.
We publish the model, not a public rate card - actual rates depend on destination, route class, volume and regulatory cost. See how every Dollu service is priced.
- A–Z rate deck in USD, EUR, GBP or INR
- Premium (CLI), Standard and Wholesale tiers per destination
- 1/1 billing on most destinations; 60/60 flagged on the deck
- Volume tiers from 1M minutes a month; bilateral and swap for carriers
- Rate increases with at least 7 days’ notice; decreases immediate
- Billing
- Prepaid (online top-up, auto-recharge) or postpaid net-15/30 after credit review; per-second increments
- Commitment
- None - month-to-month usage; optional volume commitments unlock better tiers
230+ destinations, A–Z.
Every country on the rate deck, in Premium, Standard and Wholesale tiers where the market supports them - over 600 direct carrier interconnects and Tier-1 partners. Country guides cover the destinations with the most traffic.
Enterprise Voice - your questions answered.
The questions customers and carriers ask us most often before they interconnect. If yours is not here, our team answers within one business day.
Still have a question?
Ask our solutions teamRelated services.
Services customers commonly combine with Enterprise & Business Voice.
Consolidate your global voice estate.
Share your site list and current carriers and we will return a country-by-country migration plan, indicative savings and a proof-of-concept trunk within a week.
