SMS (Short Message Service) allows users to send and receive text messages to and from mobile devices. SMS was introduced in 1991 in Europe and is supported on major mobile networks like GSM, GPRS, and CDMA. SMS messages can contain up to 160 Latin characters or 70 Unicode characters and are sent and received via Short Message Entities and a Short Message Service Center, which stores and forwards messages between mobile stations and networks.

1. SMS The Telecom Source 10 Slide Technology Series

6. SM-MT Service - SMS-DELIVER TPDU Structure PDU Type: Bits MTI bit 1 = 0 bit 0 = 0 1-10 Octets 1 Octet 2-12 Octets 1 Octet 1 Octets 7 Octets 1 Octet 0-140 Octets SCA PDU- Type OA PID DCS SCTS UDL UD 7 6 5 4 3 2 1 0 RP UDHI SRI MMS MTI User Data - Data Field of the Short Message UD User Data Length - Parameter indicating the length of the UD-field UDL Service Centre Time Stamp - Parameter identifying the time when the SMSC received the message SCTS Data Coding Scheme - Parameter identifying the coding scheme within the User Data (UD) DCS Protocol Identifier - Parameter indicating the SMSC how to process the Short Message (e.g. Fax) PID Originator Address - Address of the originating SME OA Message Type Indicator - Parameter describing the message type 00 means SMS-Deliver MTI More Messages to Send - Parameter indicating whether or not there are more messages to send MMS Status Report Indication - Parameter indicating if the SME has requested a status report SRI User Data Header Indicator - Parameter indicating that UD field contains a header UDHI Reply Path - Parameter indicating that Reply Path exists RP Protocol Data Unit Type PDU Type Service Centre Address - Telephone number of the Service Centre SCA Description Parameter

7. SM-MO Service - SMS-SUBMIT TPDU Structure Bits PDU Type: MTI bit 1 = 0 bit 0 = 1 7 4 3 2 RP UDHI SRR User Data - Data Field of the Short Message UD User Data Length - Parameter indicating the length of the UD-field UDL Service Centre Time Stamp - Parameter identifying the time when the SMSC received the message SCTS Data Coding Scheme - Parameter identifying the coding scheme within the User Data (UD) DCS Protocol Identifier - Parameter indicating the SMSC how to process the Short Message (e.g. Fax) PID Destination Address - Address of the destination SME DA Message Reference - Successive numbers (0…255) of all SMS-SUBMIT frames sent by the MS. MR Message Type Indicator - Parameter describing the message type 01 means SMS-Submit MTI Reject Duplicates – parameter indicating if SMSC will accept a message with same MR and DA from the same OA RD Validity Period Format - Parameter indicating whether or not the VP field is present VPF Status Report Request - Parameter indicating if the MS has requested a status report SRR User Data Header Indicator - Parameter indicating that UD field contains a header UDHI Reply Path - Parameter indicating that Reply Path exists RP Protocol Data Unit Type PDU Type Service Centre Address - Telephone number of the Service Centre SCA Description Parameter 6 5 1 0 VPF 1-10 Octets 1 Octet 1 Octet 2-12 Octets 1 Octet 1 Octets 0, 1 or 7 Octets 1 Octet 0-140 Octets SCA PDU- Type MR DA PID DCS VP UDL UD RD MTI

8. Message Flow SM-MT Message Transfer sendRoutingInfo- Delivery ForShortMsg forwardShortMessage sendInfoFor- MT-SMS Message Transfer Deliver Report SM-Delivery ReportStatus Report SMSC GMSC HLR MSC VLR Page Authenticate MS Note: ETSI/GSM MAP sendRoutingInforForShortMsg equivalent in IS41 (North American standard) is SMSrequest mechanism, while forwardShortMessage is Short Message Delivery-Point-to-Point (SMD-PP)

9. Message Flow SM-MO Message Transfer Delivery forwardShortMessage sendInfoFor- MO-SMS Message Transfer Delivery Report Delivery Report Report SMSC SMS-IWMSC HLR MSC VLR Access Request Authenticate MS Note: ETSI/GSM MAP forwardShortMessage equivalent in IS41 (North American Standard) is Short Message Delivery-Point-to-Point (SMD-PP) mechanism

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