本欧洲电信标准（ETS）规定了无线电接口（GSM 04.02中定义的参考点Um）用于正常操作、注册、擦除、激活、停用、询问和呼叫服务网络调用的程序。补充业务的提供和撤销是移动用户和服务提供者之间的管理事项，不会在无线电接口上发出信号。在GSM 04.10中，给出了第3层无线电接口处补充业务规范的一般方面。GSM 04.80规定了补充服务的格式和编码。补充业务的定义和说明见GS M 02.04和GSM 02.8x和02.9x系列。GSM 02.82专门与提供补充业务的呼叫有关。GSM和GSM.9x系列的补充业务在GSM.03和GSM.8x.03的技术实现中进行了描述。 GSM 03.82专门与提供补充业务的呼叫有关。第3层无线电接口的呼叫控制、移动性管理和无线电资源管理程序在技术规范GSM 04.07和GSM 04.08中定义。以下补充服务属于呼叫提供补充服务，并在本ETS中进行了描述:-呼叫转移无条件（CFU）（第1条）；-移动用户忙时的呼叫转移（第2条）；-无应答呼叫转接（CFNRy）（第3条）；-移动用户不可到达的呼叫转移（CFNRc）（第4条）。

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, interrogation and network invocation of call offering supplement ary services. Provision and withdrawal of supplementary services is an administrative matter between the mobile subscriber and the service p rovider and cause no signalling on the radio interface. In GSM 04.10, the general aspects of the specification of supplementar y 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 and GSM 02.8x and 02.9x-series. GSM 02.82 is related specially to call offering supplementary services. Technical realization of supplementary services is described in GSM 03.11 and GSM 03.8x and 03.9x-series. GSM 03.82 is related specially to call offering supplementary services. The procedures for Call Control, Mobility Management and Radio Resourc e management at the layer 3 radio interface are defined in technical s pecifications GSM 04.07 and GSM 04.08. The following supplementary services belong to the call offering suppl ementary services and are described in this ETS: - Call forwarding unconditional (CFU) (clause 1); - Call forwarding on mobile subscriber busy (CFB) (clause 2); - Call forwarding on no reply (CFNRy) (clause 3); - Call forwarding on mobile subscriber not reachable (CFNRc) (clause 4 ).