The provisions of this Recommendation are limited to enquiries concerning messages handled by an IWF in accordance with the relevant U-Series Recommendations. Status enquiry in respect of messages deposited into a telex SFU for delivery to the International Telex Service are handled in accordance with Recommendations F.72, U.80 and U.81. The provisions of this Recommendation should be applied to future implementations and, as far as possible, to existing implementations of IWF and SFU, in the latter case, as an alternative to the provisions of Recommendations F.72, U.80 and U.81 in respect of status enquiry. This Recommendation defines: a Status Enquiry Function (SEF) which will be always associated with an Interworking Function (IWF) or a store-and-forward unit (SFU); the protocols to be applied to enable a subscriber of the International Telex Service to request status information about one or more messages previously deposited; the format of the status information to be provided to a subscriber of the International Telex Service by an SEF in response to a status enquiry. The service requirements, relevant to a Status Enquiry Function are defined in Recommendation F.89.
ITU-T U.220 SPANISH-1993 Referenced Document
ITU-T F.72 International Telex Service - General Principles and Operational Aspects of a Store and Forward Facility - Series F: Non-Telephone Telecommunication Services - Telegraph Service - The International Telex Service Study Group 1; 20 pp*， 1996-04-19 Update
ITU-T U.80 International Telex Store and Forward Access from a Telex Subscriber - Telegraph Switching Telex Store and Foreward (Study Group IX) 19 pp
ITU-T U.81 International Telex Store-and-Forward - Delivery to a Telex Subscriber - Series U: Telegraph Switching Telex Store and Foreward Study Group 1; 14 pp*， 1996-04-19 Update
ITU-T U.220 SPANISH-1993 history
1993ITU-T U.220 SPANISH-1993 THE INTERNATIONAL TELEX SERVICE - TECHNICAL REQUIREMENTS FOR A STATUS ENQUIRY FUNCTION IN AN INTERWORKING SCENARIO