The network feature Operator Determined Barring (ODB) allows a network operator or service provider to regulate access by subscribers to services (Circuit/Packet Oriented and Interworking WLAN), by the barring of certain categories of incoming or outgoing calls/ Packet Oriented Services or of roaming. Operator Determined Barring applies to all bearer services and teleservices except the Emergency Call teleservice and Emergency Bearer Services; the teleservice Short Message Point-to-Point is therefore subject to Operator Determined Barring in the same way as circuit-switched calls. The application of specific categories of Operator Determined Barring to a subscription is controlled by the network operator or service provider, using administrative interaction at the HLR; this interface is not standardised.