Personal data

Under the GDPR, personal data is any information relating to an identifiable natural person — directly (name) or indirectly (phone number, license plate, customer ID). The number showing on your phone is one; a call recording is another; the voicemail content, a third. The definition is deliberately broad.

The consequence for a local business: as soon as you answer the phone, you're processing personal data, with the attached obligations — legal basis (contract or legitimate interest usually suffice for a tradesperson), minimization (collect only what's needed), security (encryption), retention (don't keep forever). A vendor answering the phone on your behalf acts as a processor: it must be bound by a contract, and you remain responsible.