Callfilter spares you the hassle of unsolicited cold calls. It automatically blocks incoming calls from numbers on a list that is continually updated using specific criteria. This service is for free.

The following numbers are usually blocked:

• Callers who do not respect the requisite level of transparency (purpose of call, company name, phone number, etc. not displayed)
• Callers who ignore the asterisk system in directories
• Callers who call at inappropriate hours (before 8 am or after 8:30 pm on weekdays, before 9 am or after 4 pm on Saturdays, or on Sundays and public holidays).
• Callers who call a customer more than once within a day
• Aggressive marketing calls (e.g. dubious sales tactics)
• Calls from numbers with an invalid format
• Numbers that many Swisscom customers have placed on their individual blacklists
• Numbers that many customers have designated as unwanted 

The Callfilter does not usually block the following numbers:

• Calls that adhere to the code of conduct of the industry association for call centres (CallNet.ch), including respect for the asterisk system and no calls at inappropriate hours.
• Calls from serious survey institutes which adhere to industry standards and are not advertising calls
• Calls from official bodies such as the Federal Statistical Office
• Calls from firms which contact their customers using different numbers than those used for advertising calls

The Swisscom Callfilter blocks undesired telemarketing calls according to up-to-date blocking lists. The blocking list is compiled to the best of our knowledge. However, it is still possible that some undesired telemarketing calls will get through. In exceptional circumstances it is also possible that some normal calls may be blocked.