Callcentric SIP Trunking

Callcentric SIP Trunking lets businesses place worldwide calls from SIP-based IP PBXs or gateways through its Pay Per Call plan. The plan has no monthly charge and includes no minutes; calls are billed at variable per-minute rates, while calls to other Callcentric members are free. It lists three included channels, permits unlimited maximum channels, and has no additional channel fee. There is no commitment, and an account deposit can be as low as $5.00. Business phone numbers are offered in the USA, Canada, and more than 35 other countries. Listed uses include offices, call centers, IVR services, and calling card providers. Callcentric says most SIP/2.0 hardware and software should be compatible and names 3CX, Asterisk, freePBX, Bria, ZoIPer, and LinPhone as software users have used successfully. Compatible equipment needs specified SIP, RTP, authentication, proxy, DNS, and codec support. The service supports Android, iOS, Linux, macOS, web, Windows, extensions, and self-hosted setups. US/Canada toll-free numbers are listed at $3.95 setup and $3.95 per month.

Callcentric’s Pay Per Call plan offers business SIP trunking without a monthly fee, but usage charges vary and there are no included minutes. Compatibility depends on supported device requirements, and the service does not support RTPS or SIPS communications.

This service may suit businesses using SIP-based PBXs or gateways for office calling, call centers, IVR, or calling card services. It is particularly relevant to teams prepared to pay variable per-minute rates and configure compatible SIP equipment.

Overview

Callcentric SIP Trunking is an outbound service for businesses placing calls worldwide through SIP-based IP PBXs or gateways. It best suits teams that already have compatible SIP equipment and want usage-based calling without a monthly trunk fee. The tradeoff is straightforward: there are no included minutes, and per-minute charges vary by destination.

Pay Per Call supports business and office calling, call centers, IVR services, calling card providers, and other purposes. Callcentric offers business numbers in the USA, Canada, and more than 35 other countries, and supports number porting, emergency calling, and toll-free numbers.

Key features

Bring your own SIP equipment

Callcentric says most SIP/2.0 hardware and software should be compatible, without limiting customers to equipment it has specifically approved. Its compatibility FAQ names 3CX, Asterisk, freePBX, Bria, ZoIPer, and LinPhone as software users have successfully used. That flexibility is useful for businesses with an existing setup, but compatibility still depends on the device meeting requirements: SIP 2.0, RTP over UDP, DIGEST MD5 authentication, a fixed outbound proxy, DNS SRV, and G.711 and/or G.729.

Calling controls and privacy

Administrators can limit allowed calling destinations and apply IP whitelisting globally or per extension; Callcentric also advises using complex passwords. The service does not support RTPS or SIPS for audio or SIP communications, so it is not the right fit when those encrypted transport methods are required. Callcentric says credentials are encrypted during REGISTER and INVITE according to SIP, and that it neither listens to calls nor has access to users’ login passwords.

Support and numbers

A maintained knowledge base, BYOD setup guides, and free support through trouble tickets give customers routes to resolve configuration issues. US/Canada toll-free numbers cost $3.95 setup and $3.95 per month. Other US/Canada and international number prices vary by product or country.

Pricing

Pay Per Call: free (billed Month to month: $0.00). The plan is outbound-only, includes three channels and zero minutes, and charges variable per-minute rates for calls; calls to other Callcentric members are free. It has unlimited maximum channels and a $0.00 additional channel fee. There is no monthly commitment, and the account deposit can be as low as $5.00.

This structure favors businesses with variable or modest outbound usage that want to avoid a recurring trunk charge. It is less predictable for organizations with sustained calling volume because there are no bundled minutes and the per-minute rates vary. Callcentric has no free trial.

Platforms

Callcentric lists Android, iOS, Linux, macOS, Windows, web, extension, and self-hosted support. In practice, the service’s equipment requirements matter more than the breadth of platform labels: a PBX, gateway, or software client must meet the SIP and codec requirements to be compatible.

Who it's for

Pay Per Call is a practical option for offices, call centers, IVR services, and calling-card providers that need outbound SIP trunking and can configure compatible equipment. Its no-monthly-fee structure and low starting deposit make it accessible for variable usage, while the three included channels provide a defined starting capacity. Businesses that need bundled minutes, predictable per-minute pricing, or RTPS/SIPS transport should look elsewhere.

Pros and cons

• Pros: No monthly fee or commitment keeps fixed costs low; calls between Callcentric members are free.
• Pros: Three channels are included, with no additional channel fee and unlimited maximum channels.
• Pros: Broad BYOD compatibility and setup guides can suit businesses already using SIP equipment.
• Cons: No included minutes and variable per-minute rates make total calling costs less predictable.
• Cons: Outbound-only service is not a complete inbound trunk solution on its own.
• Cons: Lack of RTPS and SIPS support rules it out where those transport protections are mandatory.

Alternatives

• SIP Trunking Providers is a broader comparison for readers who want to survey the category.
• Twilio Segment may suit teams looking for a freemium web, iOS, and Android product with a free plan and trial, rather than SIP trunking.
• SIP.US Cloud SIP Trunking is worth considering for readers who prefer paid plans with a free trial and per-number local DID pricing.
• SendFax.to is an alternative for businesses seeking faxing plans rather than voice SIP trunking.
• VoIP.ms SIP Trunking is a paid alternative with an inbound SIP trunk channel plan at $23 a month.
• Bandwidth Messaging API is a paid messaging API alternative with per-message SMS plans and a free trial.
• Telnyx Text-to-Speech API offers a free plan and pay-as-you-go text-to-speech pricing for API and web use.
• Telnyx SIP Trunking is another usage-billed SIP trunking option, with a $0 platform fee and usage charges per minute.
• IPComms SIP Trunking is a freemium alternative with a free trial and usage billed from a prepaid balance.

Verdict

Choose Callcentric Pay Per Call if your business already has compatible SIP equipment, needs outbound calling, and values avoiding a monthly trunk fee. Its flexible channel terms and member-to-member free calls are useful, but variable per-minute billing and the absence of RTPS/SIPS support make it a weaker fit for businesses that need predictable costs or those transport protections.