NCOS is a feature used to control call permissions and restrictions for users or devices. It determines what types of calls a user or endpoint can make, such as:

• Internal Calls Only (e.g., within the same organisation)
• Local Calls (allowing calls within a specific area code)
• National Calls (long-distance calls within a country)
• International Calls (global dialling permissions)
• Premium or FreePhone Numbers (restricting or allowing access to premium-rate services)

Level	Allowed	Blocked
NCOS-1	Internal & Emergency Calls Only	Local, National, International, Premium,118, PNS & PRS
NCOS-2	Local, National & Emergency	International, Premium,118, PNS & PRS
NCOS-3	Local, National, PNS & Emergency	International,118 & Premium
NCOS-4	Local, National, PNS, International & Emergency	Premium &118
NCOS-5	Local, National, PNS, PRS International & Emergency	118
NCOS-6	Local, National, PNS, PRS International & Emergency	Nothing

PNS = Personal Numbering Service (PNS) uses 070 numbers for personal or “follow-me” services, allowing calls to be redirected to different destinations. When someone dials a 070 number, the caller’s provider pays a wholesale termination charge to the 070 service provider to complete the call to the recipient. The cost is added directly to your phone bill, meaning you pay a premium price to access the service through a voice call.

PRS = Premium rate services are phone numbers that incur significantly higher charges than standard calls. They are commonly used for accessing content such as entertainment, information services, or voting on TV shows. The cost is added directly to your phone bill, meaning you pay a premium price to access the service through a voice call.

118118 numbers in the UK are premium-rate numbers used for directory enquiries. In addition to providing phone numbers, 118 services can also offer train times, cinema listings, and directions.

NOTE: On International calls the Default Hotlist International Call Barring is applied.