This European Telecommunication Standard (ETS) specifies the procedure s used at the radio interface (reference point Um as defined in GSM 04 .02) for normal operation, registration, erasure, activation, deactiva tion, invocation and interrogation of call offering supplementary serv ices. Provision and withdrawal of supplementary services is an adminis trative matter between the mobile subscriber and the service provider and cause no signalling on the radio interface. In GSM 04.10 the general aspects of the specification of supplementary services at the layer 3 radio interface are given. GSM 04.80 specifies the formats and coding for the supplementary servi ces. Definitions and descriptions of supplementary services are given in GS M 02.04, GSM 02.8x and 02.9x-series. Technical realization of supplementary services is described in GSM 03 .11, GSM 03.8x and 03.9x-series. The procedures for Call Control, Mobility Management and Radio Resourc e management at the layer 3 radio interface are defined in GSM 04.07 a nd GSM 04.08. The following supplementary services belong to the call restriction su pplementary services and are described in this ETS: - Barring of outgoing calls (clause 1): - Barring of all outgoing calls (BAOC) (Barring program 1); - Barring of outgoing international calls (BOIC) (Barring program 2); - Barring of outgoing international calls EXCEPT those directed to the home PLMN country (BOIC-exHC) (Barring program 3). - Barring of incoming calls (clause 2): - Barring of all incoming calls (BAIC) (Barring program 1); - Barring of incoming calls when roaming outside the home PLMN country (BIC-Roam) (Barring program 2).