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Senin, 14 Juni 2010

[Tutorial] Pengantar Membuat Aplikasi SMS

//-----------------------------------------------------------------------------------------
Dibuat oleh : Eka Riana
Nama Project : OpenSMS ver.0.1 Beta 2009
Tanggal : Awal Oktober 2009
Keterangan : Source code ini berisi tentang bagaimana cara mengirimkan pesan ke nomor handphone yang dituju
Sifat : GPL (General Public Lisence) - Open Source
Harapan : Silahkan dikembangkan untuk perbaikan agar bangsa ini menjadi BESAR
//------------------------------------------------------------------------------------------

Sebelum saya meneruskan langkah demi langkah pengantar Membuat Aplikasi OpenSMS ini, saya mohon izin kepada para sesepuh dan akang-akang (pujisusanto, mbahlawu, pujanggabageur, gyus, flack, agoesdobleb, vberror13, tatangs, k4m4r482, akhirudin, trail, g3zle, ibnuQoyyim dan yang lain-nya yang ga tertulis) dan kawan-kawan yang cukup dan sangat-sangat Advanced di bidang ini dan yang sudah saya anggap guru pribadi saya , saya cuma punya setitik pengetahuan dan hanya ingin berbagi informasi atas dasar

"Sampaikan Ilmu walaupun satu pembuktian Ilmi-ah"

Ucapan Terima Kasih :
1. Allah SWT yang telah memberikan kurnia IMAN dan pemahaman source code visual basic 6.0 walau hanya sedikit
2. Ayah dan Ibu tercinta yang telah mendahului, saya sangat rindu kepadamu. Maaf ananda belum mampu mewujudkan cita-cita Ibunda.
3. Kawan-kawanku di forum.vb-bego.com yang berubah menjadi iBego,
4. nGOpre-X Community yang tidak terurus blog-nya dan pertemuannya, mudah-mudahan kawan-kawan bisa segera menyelesaikan persoalannya ini.

Mukaddimah
Aplikasi ini salah satu aplikasi untuk mengirim SMS yang masih sangat sederhana dari sisi source code, interface dan security. Aplikasi ini dibantu dengan gammu dan MySQL sebagai databasenya. Iseng dan mempertajam daya ingat dikhawatirkan semua source code yang saya miliki luntur karena tidak sering digunakan, tapi besar harapan mudah-mudahan bisa dijadikan satu referensi bagi siapapun yang membutuhkan.

Sesuai dengan namanya OpenSMS ver.01-BETA1 2009, maka source code inipun boleh dikembangkan dan diperbaiki bahwa disesuaikan dengan yang anda suka, selain itu guna mendukung gerakan IGOS (Indonesia, Go Open Sources) dan mencerdasakan kehidupan bangsa, walaupun memang language yang digunakan bukan Open Source. Sejujurnya apapun bahasa yang nanti akan dipakai semuanya pasti bisa.

Software Pendukung
Apikasi ini membutuhkan beberapa software pendukung agar bisa berjalan sesuai dengan fungsinya yaitu mengirim SMS, antara lain software pendukung yang dimaksud adalah :
1. MySQL
2. Gammu win32 (http://www.ziddu.com/download/3428268/g ... 2.zip.html)
3. Driver Handphone (jika dibutuhkan)
4. Visual Basic 6.0

Hardware Pendukung
Selain software pendukung, tambahan hardwarepun harus dipersiapkan, dikarenakan software ini untuk mengirim sms maka beberapa hardware pendukung yang harus dipersiapkan antara lain:
1. Handphone Siement C55, Sony Ericsson
2. Kabel data
3. Bluetooth (bila ingin menggunakan fasilitas Bluetooth )

Image Image Image Image

Sebaiknya dan saran dari saya apabila kita ingin mencoba dan sudah saya uji sebelumnya Siement C55 cukup menjadi bahan pertimbangan untuk digunakan.

Rancangan Database
1. Install MySQL
    Gammu membutuhkan database yang di buat di MySQL, oleh karena itu mau tidak mau, suka tidak suka kita harus buat database tersebut di MySQL, tapi sebelum membuat Dbnya terlebih ddahulu kita harus Install dulu MySQL tersebut, untuk mudahnya tinggal kita liat di thread iniviewtopic.php?f=16&t=254
2. Create dan Import Database
    Berikut dibawah ini langkah-langkah membuat database untuk aplikasi SMS yang kita buat, hanya create dan import yang mesti kita lakukan, inilah enaknya gammu sudah menyiapkan sendiri rancangan databasenya, jadi kita tidak susah-susah buat lagi.
    1. Masuk ke web browse, untuk kali ini kita bisa menggunakan IE atau Firefox, silahkan pakai webbrowser yang anda suka.
    2. Pada Address bar ketik localhost, sehingga akan terlihat tampilan seperti dibawah ini :
      Image

    3. Berikutnya klik phpMyAdmin, maka akan terlihat tampilan seperti dibawah ini :

      Image

    4. Ketik OpenSMS pada text Create new database, dilanjutkan klik tombol Create, maka database OpenSMS sudah terbuat.
    5. Untuk membuat table didalam database selanjutnya kita klik import, maka akan terlihat tampilan seperti dibawah ini :

      Image

    6. Klik tombol browse -----> cari file mysql.sql di folder win32 pada drive C:\, klik Open bila file mysql.sql sudah dipilih. (lihat gambar)

      Image

    7. klik GO sebagai terakhir dari membuat database OpenSMS dan import 9 tabel ini, maka akan terlihat seperti ini ;

      Image

Konfigurasi Gammu
Untuk sinkronisasi antara port com dan nama database yang digunakan, maka konfigurasi gammu ini mutlak harus dilakukan, ada 2 fila gammu yang harus kita sesuaikan atau kita ubah terlebih dahulu, dibawah ini cara mengkonfigurasi 2 file tersebut.

1. File gammurc
    a. Sebelum kita ubah isi file gammurc, maka terlebih dahulu anda harus mengextrak file gammu_win32.zip yang sudah di unduh ke drive C:\
    b. Buka folder win32 yang kita extrak tadi, kemudian cari file gammurc
    c. Klik kanan file gammurc, pilih open (maka akan muncul tampilan seperti dibawah ini)

    Image

    d. Untuk mempermudah mengubah isi file maka kita harus pilih WordPad, dilanjutkan dengan klik Ok, maka akan terlihat isi file gammurc seperti dibawah ini :

    [gammu]

    port = com10: --------> yang ini harus sesuaikan dengan com di pc anda
    #model = 6110
    connection = at19200 ------> yang ini sesuaikan dengan hp yang dipakai
    #synchronizetime = yes
    #logfile = gammulog
    #logformat = textall
    #use_locking = yes
    #gammuloc = locfile
    #startinfo = yes
    #gammucoding = utf8
    #rsslevel = teststable
    #usephonedb = yes

    [gammu1]

    port = com10: --------> yang ini harus sesuaikan dengan com di pc anda
    #model = 6110
    connection = at19200 ------> yang ini sesuaikan dengan hp yang dipakai
    #synchronizetime = yes
    #logfile = gammulog
    #logformat = textall
    #use_locking = yes
    #gammuloc = locfile
    #startinfo = yes
    #gammucoding = utf8


    Keterangan:
    untuk Handphone siement C55 kita bisa menggunakan connection=at, dan untuk handphone sony Ericcson kita bisa menggunakan connection=at19200. Untuk lebih jelasnya bisa dilihat isi file gammurc dibawahnya.

    d. Simpan file gammurc yang sudah kita ubah tersebut.
    e. Terakhir, untuk melihat hasil konfigurasi file gammurc ini berhasil atau tidak maka kita harus testing terlebih dahulu dengan cara dibawah ini :
      * Masuk ke DOS dengan klik Start --> Run --> ketik cmd (lihat gambar dibawah ini)
      Image
      * Masuk ke drive C:\ dan folder win32, dengan cara ketik cd \win32 ---> Tekan Enter
      * Untuk menjalankan dan sekaligus mengecek file gammurc dan hp sudah terbaca atau belum, ketik gammu –identify ----> Tekan Enter (lihat gambar untuk lebih jelasnya)

      Image

      Keterangan :
      Setelah kita menekan tombol Enter, maka gammu akan mengidentifikasi Handphone yang kita pasang terbaca atau tidak, sebagai tanda kalau handphone yang kita gunakan terbaca maka gammu akan memberikan keterangan nomor imei dari handphone yang kita gunakan.


2. File smdrc
    Setelah file gammurc sudah kita sesuaikan dengan port com dan connection handphone yang kita gunakan, maka selanjutnya kita harus merubah isi file smsdrc, file ini harus kita sesuaikan dengan database yang kita buat. Dibawah ini potongan file dari smsdrc yang harus kita sesuaikan, dan cara membuka filenya sama dengan cara mengedit file gammurc

    # ----------------------- SETTINGS FOR --smsd MYSQL --------------------
    user = root ----> sesuaikan dengan user name mysql
    password = ----> sesuaikan dengan password user mysql
    pc = localhost ----> sesuaikan dengan host yang digunakan
    database = smsd---> sesuaikan dengan nama database yang kita buat

    # when you send sms from some SMSC, you can have Delivery/Failed Delivery
    # Reports from other SMSC number. You can set here number of this "buggy"
    # SMSC used by you and Gammu will not check it's number during assigning
    # reports to sent sms
    #skipsmscnumber = +48602123456
    # -----------------------------------------------------------------------



    Dari database yang kita buat adalah OpenSMS, dengan user mysqlnya root dan passwordnya null, sedangkan nama hostnya adalah localhost, maka seharusnya isi file smsdrc menjadi seperti dibawah ini :

    # ----------------------- SETTINGS FOR --smsd MYSQL --------------------
    user = root
    password =
    pc = localhost
    database = OpenSMS


    # when you send sms from some SMSC, you can have Delivery/Failed Delivery
    # Reports from other SMSC number. You can set here number of this "buggy"
    # SMSC used by you and Gammu will not check it's number during assigning
    # reports to sent sms
    #skipsmscnumber = +48602123456
    # -----------------------------------------------------------------------


    Jangan lupa untuk menyimpan file smsdrc tersebut.


3.Testing Service Gammu
    Dua file sudah kita konfigurasi, maka langkah selanjutnya kita coba menjalankan service gammu, service gammu ini berfungsi untuk membaca sms yang masuk dari handphone yang kita gunakan, dan mengirimkan sms yang keluar dari table outbox yang terdapat didatabase MySQL. Tidak rumit dan memusingkan otak untuk menjalankan service gammu ini, silahkan ikuti langkahnya :
    • Masuk ke DOS (ingat bukan DDOS ya aksi membombardir server, yang biasa dilakukan oleh para cracker)
    • Masuk ke direktori gammu dengan perintah CD
    • Ketik perintah gammu –smsd MYSQL smsdrc (awas jangan salah ketik baik huruf besar dan kecilnya), look in picture

      Image

    • Bila terdapat tulisan secara terus menerus maka service gammu sudah ok (jangan ditutup dan dihentikan biarkan berjalan)


Rancangan Interface OpenSMS
Sudah saatnya kita harus membuat rancangan tampilan atau antar muka pengguna dari Aplikasi OpenSMS, sebagai awal kita akan buat 1 form didalam Visual Basic 6.0, dan diharapkan anda sudah tidak lagi bingung dalam merancang form di dalam Visual Basic 6.0.
1. Silahkan buka Visual Basic kesayangan anda
2. Tambahkan 1 Form, 2 object label, 2 object text dan 2 object command serta 2 shape
3. Silahkan setting sesuai selera anda, sehingga hasilnya kalau saya setting properties seperti ini :

    Image

Saya yakin anda jauh lebih baik dalam hal desain interfacenya dari saya :D

Create Coding
Inilah sesi yang paling dan sunggung-sungguh sangat menyulitkan buat saya secara pribadi yang masih muda belia dalam hal pemrograman ini, "Nulis Coding" atau "Syntax" atau "Listing Program"

Sebelumnya saya mohon maaf kalau penulisan Codingnya tidak memenuhi standar penulisan yang sebenarnya :

1. Tambahkan 1 modul, silahkan create coding na kaya seperti ini, sebelumnya tambahkan reference Microsoft ActiveX Data Object xx library:

Public DB As ADODB.Connection
Public rsPhone As ADODB.Recordset
Public SQL As String

Public Sub Koneksi()
Set DB = New ADODB.Connection
DB.ConnectionString = "DRIVER={MYSQL ODBC 3.51 Driver};" _
& "SERVER=localhost;" _
& "DATABASE=OpenSMS;" _
& "UID=root;" _
& "PWD=;" _
& "OPTION="
DB.Open
End Sub

Public Sub TextKosong()
Dim i As Control
For Each i In FrmKirim
If TypeName(i) = "TextBox" Then
i.Text = ""
End If
Next i
End Sub
Public Sub TextMati()
Dim i As Control
For Each i In FrmKirim
If TypeName(i) = "TextBox" Then
i.Enabled = False
End If
Next i
End Sub

Public Sub TextHidup()
Dim i As Control
For Each i In FrmKirim
If TypeName(i) = "TextBox" Then
i.Enabled = True
End If
Next i
End Sub


2. Kembali ke Form KirimSMS
'-----------------------------------------------------------------------------------
'Dibuat oleh : Eka Riana
'Tanggal : Awal Oktober 2009
'Keterangan : Source code ini berisi tentang bagaimana cara mengirimkan pesan
' ke nomor handphone yang dituju
'Sifat : Open Source
'Harapan : Silahkan dikembangkan untuk perbaikan agar bangsa ini menjadi BESAR
'-----------------------------------------------------------------------------------
Private Sub CmdKirim_Click()
If CmdKirim.Caption = "&Kirim" Then
If Text1.Text = "" Or Text2.Text = "" Then
If Text1.Text = "" Then
MsgBox "Maaf Nomor Pengirim Belum Diisi", vbOKOnly + vbInformation, "Informasi"
Text1.SetFocus
ElseIf Text2.Text = "" Then
MsgBox "Maaf Isi Pesan Belum Diisi", vbOKOnly + vbInformation, "Informasi"
Text2.SetFocus
End If
Else
CmdKirim.Caption = "&Keluar"
cmdMulai.Caption = "&Mulai"
KirimSMS
TextMati Me
TextKosong Me
End If
Else
MsgBox "Silahkan Source Code ini dikembangkan (Eka Riana)", vbMsgBoxSetForeground, "Informasi"
End If
End Sub

Private Sub cmdMulai_Click()
With cmdMulai
If .Caption = "&Mulai" Then
TextHidup
Text1.SetFocus
.Caption = "&Batal"
CmdKirim.Caption = "&Kirim"
Else
.Caption = "&Mulai"
CmdKirim.Caption = "&Keluar"
TextMati
End If
End With
End Sub

Private Sub Form_Load()
Koneksi
TextKosong Me
TextMati Me
End Sub

Sub KirimSMS()
Set rsKirim = New ADODB.Recordset
SQL = "Insert Into outbox(DestinationNumber, Coding, TextDecoded) values" _
& "('" & Text1.Text & "', 'Default_No_Compression'," _
& "'" & Text2.Text & "')"
DB.Execute SQL
End Sub

Private Sub Text2_Change()
lblJumlah.Caption = 160 - Len(Text2.Text)
If Len(Text2.Text) = 160 Then
MsgBox "Maaf Jumlah Karakter Sudah Tidak Mencukupi", vbOKOnly + vbInformation, "Konfirmasi"
End If
End Sub

'yang ini ga usah di pake yah
Private Sub Timer1_Timer()
fadin = fadin - 5
If fadin >= 10 Then
MakeTransparent Me.Hwnd, fadin
Else
MakeTransparent Me.Hwnd, 255
Timer1.Enabled = False
Unload Me
FrmMe.Show
End If
End Sub


Test Program
Yang perlu di perhatikan sebelum kita test program yang sudah kita buat ini, mampu mengirim sms atau tidak, berikut dibawah ini yang perlu di perhatikan :
1. Hp sudah terpasang ke PC lewat Com1 atau Com2 atau via Bloothoet
2. Hp yang kita gunakan sudah dikenal oleh gammu dengan ciri menampilkan nomor imei hp tersebut.
3. Service gammunya sudah running (kalau belum silahkan jalankan lagi lewat command prompt)
4. MySQL sudah running


Kalau sudah semuanya ok, silahkan tekan F5 dan di coba mengirim SMS ke nomor ane 021-91975218, Insya Allah ane balas kalau ada Pulsa,,, oh iya jadi lupa yang nomor 5 nih

5. Biar testnya memuaskan kartunya enaknya ada PULSA-nya :D

Penutup
Alhamdulillahirabbil`alamin saya menyatakan syukur
Demikian tutorial Pengantar cara membuat Aplikasi OpenSMS ini, semoga bermanfaat adanya, bila ada yang kurang mohon dikoreksi dan ditambahkan demi perbaikan informasi untuk sesama.

Parungpanjang, 5 Mei 2010
Salam,


Eka Riana


Kamis, 15 April 2010

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How many SMS can be sent per minute using a GSM modem?

The exact number of SMS messages that can be sent or received using a GSM modem depends on depends on various factors like GSM network quality (signal strength, network congestion etc) and quality of GSM modem used etc. However, it is safe to assume that GSM modems can send/receive 8 to 10 SMS messages per minute.

What is a SMS Application Server?

SMS Application Server is a software tool that allows configuration and deployment of mobile messaging applications.

A SMS Application Server has inbuilt connectors for mobile enabling of enterprise information from various sources like:

- Database: Using SQL queries
- ERP: Using tools like BAPI for SAP R/3 etc or using database connector.
- Web Server: Using HTTP(S), Telnet etc
- Email Server: POP3, SMTP, IMAP etc.
- Enterprise Network: Using WMI, ADSI, Telnet etc.

SMS Application Server allow deployment of various types of mobile messaging applications like:

- Query response (Info on demand)
- Static & Dynamic Content Broadcasts
- Manual & Scheduled Content Broadcasts
- Mobile Email Notifications etc

What is a SMS Gateway?

SMS Gateway is a interface between software applications mobile networks. An SMS Gateway allows interfacing software applications to send and/or receive SMS messages over mobile network.

Typically a SMS Gateway uses either one or more GSM modems or a direct network connection (HTTP(S), SMPP, CIMD etc) with the SMSC to send and receive messages to and from mobile networks.

Software applications generally interface with the SMS Gateway either using ASCII text files, XML/SOAP or database tables. A good SMS gateway will provide the developer with a ActiveX component or a API to interact with the gateway to read/write SMS messages, thus reducing the development time for implementing mobile messaging features in software applications.

What is a GSM Modem?

A GSM Modem modulates outgoing digital signals from a computer or other digital device to signals for a GSM network and demodulates the incoming GSM signal and converts it to a digital signal for the computer or other digital device.

Strictly speaking a GSM Modem can be considered as a GSM phone without the conventional keypad and display and that it is not battery operated as the conventional GSM phone. However, most GSM phones of today have the modem functionality inbuilt into them which allows them to be interfaced with a PC and to be used as a GSM Modem.

A PC or any other digital device uses AT Commands to interact with a GSM modem. AT Commands allow a host of functions to be performed viz sending/receiving SMS, Making a voice call, Accepting a incoming voice call, Modem configuration etc.

What is the maximum length of a SMS?

Each short message is up to 160 characters in length. The 160 characters can comprise of words, numbers, or punctuation symbols.

The actual limit of size of SMS is 160 characters if Latin alphabets are used. If non-Latin alphabets like Chinese or Arabic are used, the limit is 70 characters.

Most mobile phones these days however support "long messages". When enabled, long message feature splits up messages longer than 160 characters in to multiple messages. If the recipient mobile phone has long message feature enabled then on reciving the split up messages it would join them together and display as a single message. If the long message feature is not enabled in the recipient phone then it would be displayed as multiple messages.

What is GPRS?

General Packet Radio Services (GPRS) is a packet-based wireless communication service that promises data rates from 56 up to 114 Kbps and continuous connection to the Internet for mobile phone and computer users. The higher data rates will allow users to take part in video conferences and interact with multimedia Web sites and similar applications using mobile handheld devices as well as notebook computers. GPRS is based on Global System for Mobile (GSM) communication and will complement existing services such circuit-switched cellular phone connections and the Short Message Service (SMS).

In theory, GPRS packet-based service should cost users less than circuit-switched services since communication channels are being used on a shared-use, as-packets-are-needed basis rather than dedicated only to one user at a time. It should also be easier to make applications available to mobile users because the faster data rate means that middleware currently needed to adapt applications to the slower speed of wireless systems will no longer be needed. As GPRS becomes available, mobile users of a virtual private network (VPN) will be able to access the private network continuously rather than through a dial-up connection.

GPRS will also complement Bluetooth, a standard for replacing wired connections between devices with wireless radio connections. In addition to the Internet Protocol (IP), GPRS supports X.25, a packet-based protocol that is used mainly in Europe. GPRS is an evolutionary step toward Enhanced Data GSM Environment (EDGE) and Universal Mobile Telephone Service (UMTS).

What is WAP?

WAP (Wireless Application Protocol) is a specification for a set of communication protocols to standardize the way that wireless devices, such as cellular telephones and radio transceivers, can be used for Internet access, including e-mail, the World Wide Web, newsgroups, and Internet Relay Chat (IRC). While Internet access has been possible in the past, different manufacturers have used different technologies. In the future, devices and service systems that use WAP will be able to interoperate.

The WAP layers are:

- Wireless Application Environment (WAE)
- Wireless Session Layer (WSL)
- Wireless Transport Layer Security (WTLS)
- Wireless Transport Layer (WTP)

The WAP was conceived by four companies: Ericsson, Motorola, Nokia, and Unwired Planet (now Phone.com). The Wireless Markup Language (WML) is used to create pages that can be delivered using WAP.

There are other approaches to an industry standard besides WAP, including i-Mode.

What is SMSC?

SMSC is an abbreviation for the words Short Message Service Centre. An SMSC provides a number of services, in particular the regulation of the transfer of text messages between mobile phones. When a user sends a text message (SMS message) to a recipient, the phone actually sends the message to the SMSC. The SMSC stores the message and then delivers it to the destination recipient when they are available. The SMSC usually has a configurable time limit for how long it will store the message, and the user can usually specify a shorter time limit if they want.

Additionally the message centre will take care of any charging that needs to take place. Generally speaking there is at least one Short Message Service Centre (SMSC) per network. For bulk transmission and reception of SMS messages, SMSC's have conventional, fixed, network interfaces as well as mobile network interfaces. A number of protocols have been defined to support this sort of wire-line access. SMPP is the most commonly used of these protocols.

How does SMS work?

Short message service is a mechanism of delivery of short messages over the mobile networks. It is a store and forward way of transmitting messages to and from mobiles. The message (text only) from the sending mobile is stored in a central short message center (SMSC) which then forwards it to the destination mobile.

The figure below shows a typical organization of network elements in a GSM network supporting SMS.

The SMSC (Short Message Service Center) is the entity which does the job of store and forward of messages to and from the mobile station. The SME (Short Message Entity), which is typically a mobile phone or a GSM modem, can be located in the fixed network or a mobile station, receives and sends short messages.

The SMS GMSC (SMS gateway MSC) is a gateway MSC that can also receive short messages. The gateway MSC is a mobile network’s point of contact with other networks. On receiving the short message from the short message center, GMSC uses the SS7 network to interrogate the current position of the mobile station form the HLR, the home location register.

HLR is the main database in a mobile network. It holds information of the subscription profile of the mobile and also about the routing information for the subscriber, i.e. the area (covered by a MSC) where the mobile is currently situated. The GMSC is thus able to pass on the message to the correct MSC.

MSC (Mobile Switching Center) is the entity in a GSM network which does the job of switching connections between mobile stations or between mobile stations and the fixed network.

A VLR (Visitor Location Register) corresponds to each MSC and contains temporary information about the mobile, information like mobile identification and the cell (or a group of cells) where the mobile is currently situated. Using information form the VLR the MSC is able to switch the information (short message) to the corresponding BSS (Base Station System, BSC + BTSs), which transmits the short message to the mobile. The BSS consists of transceivers, which send and receive information over the air interface, to and from the mobile station. This information is passed over the signaling channels so the mobile can receive messages even if a voice or data call is going on.

What is SMS?

Short Message Service (SMS) is the ability to send and receive text messages to and from mobile telephones. The initial standards were first discussed in the early 1980s but the world’s first commercial SMS service by Radiolinja Oy in Finland was not introduced until 1992. SMS was created as part of the GSM Phase 1 standard.

Each short message is up to 160 characters* in length. The 160 characters can comprise of words, numbers, or punctuation symbols. Short messages can also be non-text based such as binary.

The Short Message Service is a store and forward service, this means that messages are not sent directly to the recipient but via a network SMS Centre. This enables messages to be delivered to the recipient if their phone is not switched on or if they are out of coverage at the time the message was sent - so called asynchronous messaging just like email. Confirmation of message delivery is another feature and means the sender can receive a return message notifying them whether the short message has been delivered or not. In some circumstances multiple short messages can be concatenated (stringing several short messages together.

* The actual limit of size of SMS is 160 characters if Latin alphabets are used. If non-Latin alphabets like Chinese or Arabic are used, the limit is 70 characters.

What is GSM?

GSM (Global System for Mobile communication) is a digital mobile telephone system that is widely used in Europe and other parts of the world. GSM uses a variation of time division multiple access (TDMA) and is the most widely used of the three digital wireless telephone technologies (TDMA, GSM, and CDMA). GSM digitizes and compresses data, then sends it down a channel with two other streams of user data, each in its own time slot. GSM uses three frequency bands.

GSM 900 - operates in the 900 MHz frequency range and is the most common in Europe and most of the world.
GSM 1800 - operates in the 1800 MHz frequency range and is found in a growing number of countries already using GSM 900.
GSM 1900 (also called PCS (Personal Communication Services) 1900) - is used in the United States and Canada.

GSM is the de facto wireless telephone standard in Europe. GSM is available in more than 200 countries, according to the G
Terbitkan Entri
SM MoU Association. Since many GSM network operators have roaming agreements with foreign operators, users can often continue to use their mobile phones when they travel to other countries.

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