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.