SR 784.101.112/1.7 Calling-line identification
This document sets out the requirements for telecommunications service providers on transmitting the calling line number.
New requirement in the fourth edition (applies to landline numbers from 1 January 2026 and mobile numbers from 1 July 2026):
Transit providers must provide a Swiss caller number to identify calls originating abroad. The identification must also give the name of the transit provider that has carried out the identification. If the call cannot be identified on technical grounds, the transit provider must remove the caller number (requirement 2, chapter 5).
This enables the terminating provider to better recognise calls with spoofed numbers and, in accordance with Article 26a paragraph 6 OTS, to remove the number of the calling line for the line being called or to block the call entirely.
Details on the technical implementation can be found in asut’s Swiss TSP Anti-Spoofing Agreement Technical Specification.
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