The breakthrough insight: All numbering information already exists in each Communication Provider's own databases. We don't need to centralize it. We just need to query it.

The PSTN2 architecture relies on a process to locate up to date information about a phone number directly from the CP that controls that number. This process negates the need for a physical Central Database.

PSTN2 enables multiple capabilities: Real-time authentication to stop fraud, Direct routing to reduce costs, End-to-end encryption for privacy, Call Branding to know when the Bank is really calling you, Improved emergency location data to enhance or replace overnight updates, and most importantly, an open messaging exchange framework to enable any process to be automated such as Porting Fault Tracing and Diagnostics.

Here's the key: Participation is optional. CPs can adopt at their own pace or not at all. PSTN2 calls connect directly and non-participating calls fall back to traditional PSTN. No big bang, No forced migration, Just incremental voluntary improvement driven by customer demand for new functionality.

Compare: A traditional central database costs millions, takes years to build, and creates a single point of failure. PSTN2 costs nothing centrally, and CPs invest no more than they would have done to use a Central Database. Indeed, PSTN2 setup costs are reduced with freely available tested software frameworks, allowing CPs to gain value and make savings rapidly. In addition, Artificial Intelligence advances mean APIs are no longer needed to integrate legacy systems reliably, a challenge that was historically used against a Central Database.

Here's how a CP can obtain all available information about a phone number. First, they check their local cache to see if they already have it. All processes contain an invalidate cache response to ensure CPs cache values are up to date. If the cache is missing the data, or has become invalidated, they start by using Ofcom's S1 to S9 lists to locate the Range Holder for the number block. The CP sends a request to that Range Holder. The Range Holder may respond directly, or may provide a redirect if the number has been ported, in which case the CP tries there instead. The CP updates their cache, and goes direct next time. The solution means there is no need for a central database.

The root for all numbering information is the region's Regulator. This presentation is focused on the UK and Ofcom. The PSTN2 program will share how numbering data can be obtained for global expansion. For the system to work, the Regulator needs to augment numbering information with the URL of the Rangeholder that handles each number block so CPs can contact them electronically. CPs would cache downloads rather than querying continuously, and multiple bodies can provide copies for availability, but the Regulator may decline to host this information. This would require a body or bodies to step in and provide a single source of truth. This would be unfortunate as this would create a security attack vector and need strict governance. For this reason one of the early focus efforts for the PSTN2 success will be to persuade the regulator to host an extra field of data on their numbering files.

Security is fundamental. Zero trust: every message is challenged and verified. Encrypt everything: TLS for signaling, unique SRTP keys for each call. Data minimization: only share what's actually needed, only with authorized parties.

Operators needn't build everything. Managed Access Providers (MAPs) can offer hosted solutions: API endpoints, directory services, security, web portals. Small CPs participate without major investment, and larger CPs can dip their toe in the water to if benefits are real. MAPs compete on service and price. It is expected that existing wholesale carriers will offer their customer base MAP services to connect to the PSTN2, and this should be a valuable new revenue stream with a near zero consumption cost.

Visit PSTN2.org to download working code, read the complete specification, and join the movement toward a safer, more secure telecommunications network. No central database. No massive cost. Just better technology, available now.