This specification describes the supplementary services belonging to the group CALL OFFERING SUPPLEMENTARY SERVICES. The general aspects@ including definitions and recommended provision@ of the description of the supplementary services are given in specification 3TS 22.004. The group of supplementary services CALL OFFERING SUPPLEMENTARY SERVICES is divided into four different supplementary services: - Call forwarding unconditional (section 1); - Call forwarding on mobile subscriber busy (section 2); - Call forwarding on no reply (section 3); - Call forwarding on mobile subscriber not reachable (section 4). Indication of active Call forwarding supplementary service. An indication that a Call forwarding service is currently active and operative on a number will be given to the forwarding party each time an outgoing call is made. There will be one indication for Unconditional call forwarding and another common indication for the Conditional call forwarding services. Note on the use of the forwarded-to number at registration. If the forwarded-to number is a number in the HPLMN country@ it may be entered by the served mobile subscriber in three different formats@ independent of her actual location@ according to the schemes: 1) National (significant) number. 2) National (trunk) prefix plus national (significant) number. 3) International prefix*@ country code@ national (significant) number. Scheme 3) Storage of numbers in this format is mandatory for all PLMN operators. If the forwarded-to number is a number in a country other than the HPLMN country@ it shall be entered by the served mobile subscriber@ independent of her actual location@ according to the following scheme: - International prefix (NOTE)@ country code@ national (significant) number. NOTE: The MMI for entering of international prefix is defined in 22.030. The maximum forwarded-to number length is 28 digits. Principles for interaction with the Barring of Outgoing Calls supplementary services. Numbers allowed to call according to the Barring of Outgoing call service condition are allowed as forwarded-to numbers for the served mobile subscriber. Numbers not allowed to call according to the Barring of Outgoing call service condition are not allowed as forwardedto numbers for the served mobile subscriber. For Unconditional Call Forwarding the forwarded leg is treated as an outgoing call from the HPLMN country. For the Conditional Call Forwarding services the forwarded leg is treated as an outgoing call from the LPLMN (HPLMN or VPLMN) country. Principles for interaction with the Barring of Incoming Calls supplementary services. When Barring of all incoming calls is active for the served mobile subscriber - no Call forwarding services are allowed for her. When Barring of all incoming calls when roaming outside the HPLMN country is active and operative - i.e. the served mobile subscriber is roaming outside the HPLMN country@ the Conditional Call Forwarding services are not allowed.