TPDU Tham số TPDU của kiểu SMS-SUBMIT chứa các thông số được liệt kê trong Bảng . Các tiêu chuẩn SMS xác định ba đại diện cho các giá trị số và các giá trị chữ và số được gán cho các thông số TPDU. những đại | 116 Mobile Messaging Technologies and Services An external SME can request the following operations from the service center Submit message segment this operation is for sending a message segment to an SME. Delete message segment this command is used for deleting a previously submitted message segment. Replace message segment this operation allows the replacement of a previously submitted message segment which has not been delivered yet by a new message segment. Delete all message segments delete all previously submitted message segments which have not been delivered yet. Enquire message segment request the status of a previously submitted message segment. Cancel status report request this operation is for canceling a request for the generation of a status report related to the previous submission of a message segment. Alert SME request this command allows alerts when a specified SME has registered. Login this operation allows users to access to the SMSC remotely. Change password this operation allows users to change their password. Get subscriber information this operation allows an SME to query the network HLR to determine if a network node is currently serving a mobile station. The SMSC can request the following operations from the external SME Alert SME this operation is used by the SMSC to indicate to the SME that a mobile station has registered in the network. Status report this operation is used by the SMSC to provide a status report to the external SME. The status report indicates the status of the corresponding message segment delivery. Incoming message segment this operation is used by the SMSC to provide an incoming message segment addressed to the SME. MMAP and SMAP As previously indicated access protocols initially developed to allow interactions between SMSCs and external SMEs are binary protocols. In addition SMS Forum8 has published the specifications for Short Message Application Part SMAP an XML format for defining requests and responses .