The Connected Services Framework (CSF) is an industry-led standard that simplifies switching between business communications providers, ensuring the process is straightforward, consistent, secure, and compliant.

Unlike costly alternatives, CSF can be hosted directly by a communications provider (CP) or through a Managed Access Provider (MAP). It provides a common approach that reduces complexity while remaining flexible enough to meet both industry-wide and individual provider requirements.

Developed by the Technical Architecture Group (TAG)—a collaboration of leading telecom platform providers—CSF v2.0 focuses on business switching, with plans to expand into OTS number porting, wholesale ordering, and outage notifications.

Once adopted by a number of organisations, the intention is to register this standard with an appropriate standards body.

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About CSF

The Connected Services Framework (CSF) is an open, industry-led initiative that standardises communication between telecom providers across the UK.

Built by the Technical Architecture Group (TAG).
Open framework: no license costs, available for any CP or MAP.
Establishes shared standards for secure, direct, and efficient provider-to-provider communication.
Designed to reduce costs and simplify compliance with regulatory obligations.

The CSF framework topology is summarised in the following diagram:

Why CSF Matters

Under Ofcom’s General Conditions (C7 – Switching), business service providers must manage switching when customers move to them. Unlike consumer switching (OTS), which is centrally coordinated, business switching has no single system—leaving over 4,500+ providers to manage processes individually.

This leads to:

Inconsistent and fragmented approaches.
Higher costs and complexity.
Compliance challenges for smaller providers.

CSF solves this by providing a common, standards-based method for transmitting switching messages. This:

Creates a level playing field across the industry.
Ensures consistency and interoperability across providers.
Lowers the cost of compliance.

The benefits of the adoption of this standard for Switching for Business are shown in the following diagram.

Who is involved

The TAG group (active since April 2024) is driving CSF development. Current members include:

CSF Member	Website	Contact	Services to multiple CPs
NowYoYo	nowyoyo.com	sales@nyy.global	Yes
TNS Inc. (iconectiv)	https://ukonetouchswitch.com/	bfabrykant@iconectiv.com	Yes
CWP/CSP	cwpuk.org	memberships@cwpuk.org	Yes
ICUK	icuk.net	sales@icuk.net	Yes
The Communications Gateway	comgw.uk	chris@comgw.co.uk	Yes

Future members could include MAPs offering managed GPLB services and CPs looking to automate intra-CP communications through CSF.

Overview

The CSF standard that was been created incorporates many improvements over the current transport of the OTS messages (via TOTSCo).

Key standard definitions that have been incorporated are:

Alignment as much as possible to the OTS message transport standard to minimise any additional development for any provider already offering OTS services.
Transport of the proposed GPLB message protocol as proposed by the Office of the Telecommunications Adjudicator (OTA).
Process for on/off boarding new providers who wish to adopt the CSF.
Specification of the CP directory
Secure handling of messages using transport and application level security and associated signatures.
Message signings and CP verification using DNS
Service resilience
Change management process
CP transitioning process
Handling of inflight orders
Operational monitoring process
Outage notification and service levels

The latest CSF is published into parts. CSF v2.0 – Part 1 covers the CSF Overview and a desription of the CSF Framework. CSF v2.0 – Part 2 covers the implementation of the CSF. The following buttons take you to the fully searchable markdown document.

CSF v2.0 Part 1 (Overview)

CSF v2.0 Part 1 (Framework)

CSF v2.0 Part 2 (Implementation)

You can also download the full CSF Standard (Parts 1 & 2) or our short overview CSF Handbook in pdf format:

Download Full CSF v2.0

Download CSF v2.0 Handbook

News

The Technical Architecture Group announces its Connected Services Framework for the UK telecom industry to aid business switching and other collaborative processes September 17, 2025
Last year the One Touch Switching (OTS) Hub was launched by The One Touch Switching Company (TOTSCo) as a central hub to facilitate consumer broadband and telephony switching. A central hub was a regulatory requirement for the industry to ensure a common consumer experience. For business switching business Internet Service Providers (ISPs) must follow a gaining provider led process since… Read more: The Technical Architecture Group announces its Connected Services Framework for the UK telecom industry to aid business switching and other collaborative processes
Updated CSF Governance stuctureMay 13, 2026
The TAG has now updated its governance structure shown on this page lower down in the Governance section. The inforgraphic summarises this and a detailed CSF Governance document together with our Communication Provider Charter makes it clear how CSF Members work together for the benefit of the UK CP industry.
CSF v2.0 LaunchedJune 25, 2026
26-Jun2026The Telecom Technical Architecture Group (TAG) are pleased to announce its v2.0 of the Connected Services Framework. This version build on the v1.0 work launched last May 2025. The principles are still the same, the CSF is still fully backward compatible with v1.0 and its documentation has been significantly overhauled and now includes the Part 1 CWP Overview, the Part… Read more: CSF v2.0 Launched

Join CSF

Membership Process

Any MAP or CP can join CSF by:

Implementing the CSF standard in their systems.
Completing sponsorship testing, where an existing member validates the new API connection and messaging.
- Sponsorship operates on a cost-recovery basis.

Governance

New members must sign the CSF Memorandum of Understanding (MoU), which defines a governance outline and collaboration.
The MoU is updated periodically, and members may be asked to sign new versions.
Underpinning this CSF MoU is our CSF Governance. See CSF v2 – Part 1 Section 10 and the associated CSF CP Rights Charter (or download pdf) that explains how CSF MAPs support and interact with its Communication Provider customers and how CPs make best use of the services from CSF MAPs.

The following infographic explains how we operate as a group and the governance structure we have put in place without making this overly heavy on administration:

Connected Services Framework · Part 1, Chapter 10 GOVERNANCE AT A GLANCE · v1.1 · 04 · 2026

How CSF Governance works, as the TAG now operates.

A summary of the standards landscape, the TAG’s change process, and the nine governance controls ratified by the steering group on 29 April 2026.

At a glance

The CSF is an open technical standard maintained by the TAG, sitting on top of standards held by OTA2, TOTSCo, and GPLB-SG.

Governance is decentralised by design — the §10.6 controls strengthen it without adding heavy administration.

Download the current MoU

MoU Extension

Benefits of Membership

Access to an automated, efficient mechanism for message transport.
Industry-wide interoperability through standard protocols.
Participation in the ongoing evolution of CSF.
Ability to grow faster by reducing complexity and compliance costs.

Contact

📧 Email: info@csf-uk.org
📍 Address: Gemini House, Stourport Road, Kidderminster, England, DY11 7QL
📞 Phone: (+44) 020 3051 3453

Member Portal

If you are a CSF member, you can access shared documents and resources via the link below.

CSF Member portal