Specifications

Chapter 3. SMS Messaging Server design
2. Short Message Service (SMS)
2.1. Introduction
The Short Message Service (SMS) is part of the GSM specification and allows messages to be
sent to and from GSM mobile networks throughout the world. A single short message can
contain up to 160 characters and comprise of words, numbers or an alphanumeric combination.
Short messages can be received with voice, data and fax calls. SMS also provides confirmation
that a short message has been delivered to its destination. Non-textual short messages can also
be sent to carry 8-bit binary data. Messages comprising of Unicode character sets which include
Arabic and Chinese characters can also be carrier in SMS.
SMS is a store and forward service where a short message is sent via a Short Message Service
Center (SMSC). An advantage of this is that the destination mobile device does not have to be
on the network at the time when the message is sent. If a destination mobile device is not
available at the time the message is sent, the SMSC service center will retry to deliver the
message.
Delivery of a short message takes only a few seconds from SMSC to the mobile device.
SMS messages can be up to 140 octets or 160 characters in length and can carry information
coded in different ways. The most common ‘coding scheme’ is the GSM default alphabet. This
allows a simplified text alphabet to be coded into 7 bits per character.
Most advanced applications will typically use 8-bit data where the SMSC makes no assumptions
on the coding scheme and allows applications to use the 140 octets as they wish.
2.2. GSM modems
SMS Messaging Server supports GSM modems to send and receive SMS Messages. It supports
a broad range of GSM modems that support the ETSI GSM 07.05 guidelines. Modern GSM
devices (made by Nokia, Siemens, Sony Ericsson, etc.) use the similar subset of AT+C
command set and are – as a result – also supported by ActiveXperts SMS Messaging Server.
You can connect a GSM modem through one of the following interfaces:
 Serial port;
 USB interface;
 Bluetooth;
 Infrared.
SMS Messaging Server supports TAPI drivers (like ‘Standard 9600 bps Modem’) to make
configuration of GSM modems easier. Using TAPI, you can configure the baud rate,
initialization strings, etc. through the standard Windows Control Panel.
ActiveXperts recommends MultiTech MTCBA-G-UFx modems and WaveCom 1306B GSM
modems.
ActiveXperts bundles the SMS Messaging Server software with a MultiTech modem: