Universal Computer Protocol – External Machine Interface (UCP-EMI) is a transfer protocol enabling users to interact with an SMSC. The protocol defines the information which needs to be exchanged between the user and the SMSC and the operations associated with the exchange of SMS messages. Every request made using UCP-EMI has an associated response, either positive or negative.
The Universal Coded Character Set (UCS) is a standard set of characters defined by the International Standard ISO/IEC 10646, Information technology — Universal Coded Character Set, which is the basis of many character encodings, improving as characters from previously unrepresented writing systems are added.
The User Data Header (UDH) is a block of octets added to the beginning of the user data part of an SMS message. Due to the way an SMS message is limited to a maximum size of 140 bytes, the available user data length is reduced when a UDH is included. Its purpose is to inform the mobile handset of the type of data and data length of the user data part of an SMS message. Generally, the UDH is either used in combination with binary content known as smart messaging for ringtones, operator logos, WAP Push and vCards, or it is used for concatenated SMS. Binary content can also span across multiple message parts and therefore the UDH may contain both a smart message and a concatenation header.
Universal Mobile Telecommunications System (UMTS) is one of the third generation (3G) cell phone technologies. To differentiate UMTS from competing network technologies, UMTS is sometimes marketed as 3GSM, emphasizing the combination of the 3G nature of the technology and the GSM standard which it was designed to succeed.
Unicode is a computing standard created for handling the writing systems of almost all modern and historic languages. It ensures that, regardless of the character set used by a language, computers can encode, represent and transmit the data successfully.
Username is a Sinch term used to define a distinct service that can be used to send SMS. Each username will have a different password and can have different routing and pricing associated with it. When price updates are sent out, they will be separated out by username.
Unstructured Supplementary Service Data (USSD) is a GSM service that allows a phone to create a session with a software application (typically in the mobile operator’s network). Unlike SMS, USSD is a session-based protocol which allows for real time interaction between the software and the end user. The most common use of USSD is by operators themselves to enable end users to check their balance, re-provision settings, and check settings for example, getting your IMEI code can be done by dialling *#06#. Note that this should not be confused with ** codes, which are actual dial-able short numbers.
Coordinated Universal Time - UTC replaced Greenwich Mean Time on 1 January 1972 as the basis for the main reference time scale or civil time in various regions. Time zones around the world are expressed as positive or negative offsets from UTC. Local time is UTC plus the time zone offset for that location, plus an offset (typically +1) for daylight saving time, if in effect. UTC is also referred to by the military and civil aviation as Zulu time (Z).