This technical specification specifies the procedures used at the radio interface for normal operation@ registration@ erasure@ activation@ deactivation@ invocation and interrogation of line identification supplementary services. Provision and withdrawal of supplementary services is an administrative matter between the mobile subscriber and the service provider and cause no signalling on the radio interface. In technical specification GSM 04.10 the general aspects of the specification of supplementary services at the layer 3 radio interface are given. Technical specification GSM 04.80 specifies the formats and coding for the supplementary services. Definitions and descriptions of supplementary services are given in technical specifications GSM 02.04 and GSM 02.8x and 02.9x-series. Technical specification GSM 02.81 is related specially to line identification supplementary services. Technical realization of supplementary services is described in technical specifications GSM 03.11 and GSM 03.8x and 03.9x-series. Technical specification GSM 03.81 is related specially to line identification supplementary services. The procedures for Call Control@ Mobility Management and Radio Resource management at the layer 3 radio interface are defined in technical specifications GSM 04.07 and GSM 04.08. The following supplementary services belong to the line identification supplementary services and are described in this technical specification: - Calling line identification presentation (CLIP) (section 1); - Calling line identification restriction (CLIR) (section 2); - Connected line identification presentation (COLP) (section 3); - Connected line identification restriction (COLR) (section 4).