Telecommunication operators are a provider of electronic communication services (ECS). Operators offer customers direct connections to the messaging services via telecommunication protocols such as HTTPS. Such transmission is not a "transfer" of personal data under the GDPR, but a distinct and separate activity, whereby the data in transmission is protected by confidentiality obligations

Rights to privacy and confidentiality are protected by various articles of the Charter of Fundamental Rights of the European Union:
(1) The right to confidentiality is protected by Article 7.
2. The right to privacy is set out in Article 8.

On that part, ECS must be considered as data controllers because ECS are subject to specific data protection regulations (confidentiality vs privacy). By providing ECS data is processed opaquely by the ECS provider, namely transmission
of signals/messages/voice and billing of the transmission service.

Therefore, ECS and ECN (electronic communication network) providers do not provide data processing on behalf of the customer and the provisions of data processing agreements are not suitable for the provision of ECS.

Article 95 of the GDPR stipulates that the Regulation shall not impose obligations on providers of public ECS and operators of public networks that exceed the obligations already laid down in the ePrivacy Directive.

ECS providers are prohibited from noting the content of any communication they convey, including personal data that may be part of such communication (see Article 5 of the ePrivacy Directive 2002/58/EC), unless the formal consent was given by one of the parties taking place in the transmission.

As a result, personal data included in mediated communications is not disclosed and is not "processed" by them. Otherwise, every telephony service provider would be considered a processor for every phone call it creates for the caller.