 Darshan Pandit, Assistant Professor, Department of Computer Science and Engineering from Walton's Institute of Technology, Solapur. Today we are going to discuss about GSM services. So at the end of the session student will be able to identify various services provided by GSM. So GSM services are divided in three types that is barrier service, telematic service and supplementary service. So previously GSM was known as Group Special Mobile and it was founded in 1982 and nowadays it is known as Global System for Mobile Communication. So in mobile communication digital cellular technology used for transmitting mobile voice and data services and ITU that is International Telecommunication Union plays important role for worldwide coordination of telecommunication activities in wired and wireless. And in wireless ITU-R handles standardization and also handles frequency planning. So ITU-R is divided in three regions, region one consists of Europe, Middle East countries of Formosovet, Union and Africa, region two consists of Greenland, North and South America, region three consists of Far East, Australia and New Zealand. So we are having various types of GSM. So this GSM are used in voice and digital data that is for internet and voice and message services. So GSM 850 it is used in region two, uplink for GSM 850 is 824-849 and downlink is 869-894 and channel result are 128-251 and it is also known as GSM 800. So uplink is nothing but whenever you are transmitting any data from mobile phone to base station it is known as uplink and whenever you are transmitting data from base station to mobile station it is known as downlink. And same with PGSM it is used in region one and region three and uplink is for 892-915 and downlink is 935-960 and channel result are 121-124 that is also known as primary GSM. So in the same way we are having extended GSM, railway GSM, trunking GSM, digital cellular system and PCS that is personal communication service which is used in region two. So this is the graph which shows number of mobile phone user worldwide from 2002 to 2018. So it is an increasing graph day by day the mobile users are increasing. So characteristics of GSM first is communication. So in communication user are mobile that is they can move anywhere that is one place to another and it have wireless communication and it also support for voice and data service. And GSM also supports for total mobility that is through one chip card it enables use of access point and different service provider. So it can also have international access through one chip card. So GSM also supports worldwide connectivity that is one number can be used to connect any network and handle localization that is it can call to any mobile phone or any landline phone. So GSM have high capacity because of smaller cell and it has better efficiency and we can have more number of customer per cell. So GSM also have high transmission quality that is we can send high audio video to the send from sender to receiver with uninterrupted phone call at high speed and it also provides security functions which have access control, authentication via chip cards and ping. So GSM services are divided in three types barrier service, tele service and supplementary service. So MS is nothing but mobile station, TE is terminal, MT is mobile termination. So mobile termination performs all network specific tasks like time division multiple access, frequency division multiple access and coding. So GSM PLMN is nothing but GSM public land telephone network, PSTN is nothing but public service telephone network, ISDN is integrated service digital network. So in this R interface is a reference point between non-ISDN device and terminal adapter TA which provides translation to and from such a device. And S interface is a reference point also known as S0 which is a user network interface reference point for basic rate access in ISDN environment. Also UM is nothing but air interface for GSM mobile telephone standard and U is a reference point which is a basic rate interference in a local loop of ISDN and characterized by the use of two wire transmission system that is NT1 and line termination. So yeah barrier service comprises of all service that enables the transparent transmission of data between interfaces and network. So barrier service are connection oriented and circuit or packet switched. So these services only need lower three layers of OSI reference model in which transparent barrier service only use functions of physical layer 1 to transmit data and this service do not try to recover lost data. And non-transparent barrier service use protocols of layer 2 and layer 3 to implement error correction and flow control. So barrier service also provide data service either in a synchronized way or a synchronized way. So if it is using synchronized way then it uses 2.4 or 4.8 9.6 kilo bit per second and in a synchronized way it can use 300 to 1200 bit per second. So we can have examples of barrier services all of you are using data service that is internet at high speed circuit switched or you are using gprs 2g 3g so this all comes under barrier service. So just think and write what is barrier service? So barrier service or data service is a service that allows transmission of information signal from a network interface. So next is tele-service, tele-service is a replication specific and with us need all seven layers of OSI reference model. So it compresses encrypted voice transmission message service and basic data communication with terminal as known from PSTN or ISDN network. So tele-services provide all telephone services, voice message service, emergency service, fact transmission, message service up to 160 character that is it can also have EMS that is extended message service which can have character up to 170 and above 170 character it is known as MMS that is multimedia message service. So last service is supplementary service. Supplementary service offer various enhancement for standard telephone service. So these services vary from service provider to service provider. So service provider or nothing but ATL, IDEA, Vodafone this all are service provider. So user identification, call redirection and forwarding of ongoing call, close group or multi-party communication, call conferencing, call waiting, call hold, call bearing so this all services comes under supplementary services. So these are the references which I have used to create this video, thank you.