SMS Dispatch Manager

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GSM Modem setup  

The gsm modem setup is a very important phase of the SMS Dispatch Manager installation. A good and reliable communication between the software and  the modem and between the modem and the gsm network is mandatory for well working operation.

In fact, the configuration process is related to three distinct phases:

  1. The computer serial port settings
  2. The internal modem settings (Message character code, etc)
  3. The GSM network parameters (PIN Code, SMSC, etc.)

The first step consists of the physical connection of the modem to the computer serial COM port. Preliminary, you should insert the SIM that your GSM network operator gave you in the modem.

carte SIM

Remarks: You should not install any modem drivers under Windows neither any application provided with your modem. SMS Dispatch Manager will not work properly and will not be able to connect to the modem if any other application has hooked the COM port directly.

gsm modemgsm modem setup

When this is done you can access the Setup dialog box and enter in the modem settings tab.

gsm modem setup  

The settings available there are the recommended ones.

In this example, the PIN code is not entered here because our GSM network operator doesn’t require one for this contract.

In this example, the Service Center is not specified because it is by default set in the SIM module provided by our operator

The options are explained in details in the following table:

Communication Port Settings  
Option Description

The Port property specifies the serial port or the virtual serial port of the computer to which the GSM Modem or Phone is connected.

Baud Rate

The BaudRate property specifies the baud rate at which the connected GSM Modem or Phone communicates with the computer.

Data Bits The DataBits property specifies the communication Data Bits size between GSM Modem or Phone and the computer.
Parity The Parity property specifies the type of parity check for communication between GSM Modem or Phone and the computer.
Stop Bits The StopBits property specifies the communication Stop Bits size between GSM Modem or Phone and the computer.
Modem Settings  
Option Description

Specifies the PIN (Personal Identity Number) for activating the services in the GSM Modem or Phone, if the SIM (Subscriber Identity Module) is PIN protected.
A personal identification number (PIN) is a secret numeric password shared between a user and a system that can be used to authenticate the user to the system.

Delay after PIN

Specifies the delay in milliseconds after sending the PIN to the GSM Modem (if the SIM is PIN protected). This delay allows the modem to be ready to accept further commands after sending the PIN.
Increase this value if there is a persistent network registration error problem.

Service Center


SMS center (SMSC) is responsible for handling the SMS operations of a wireless network. When an SMS message is sent from a GSM mobile phone or a GSM modem, it will reach an SMS center first. The SMS center then forwards the SMS message towards the destination.
The main duty of an SMSC is to route SMS messages and regulate the process. If the recipient is unavailable (for example, when the mobile phone is switched off), the SMSC will store the SMS message. It will forward the SMS message when the recipient is available. Very often an SMSC is dedicated to handle the SMS traffic of one wireless network. A network operator usually manages its own SMSC(s) and locates them inside its wireless network system. However, it is possible for a network operator to use a third-party SMSC that is located outside the wireless network system.

Normally, the SMSC address is pre-set in the SIM card by the wireless network operator, which means you do not need to make any changes to it.

You must know the address of the wireless network operator's SMSC in order to use SMS messaging with your mobile phone. Typically an SMSC address is an ordinary phone number in the international format.

Disable PIN Status Check

Disable PIN Status Check property should be checked only if it is sure that the application will never be used with a PIN protected SIM.Certain modems do not support checking of PIN status of the SIM and for such modems it is useful to set the Disable PIN Status Check property to checked.

Send Delay

The SendDelay property is used, which defines the minimum time delay interval between two consecutive messages in seconds.

Send Retry

At times due to various reasons the sending of a message may fail in its first attempt (e.g. low network signal strength, network busy etc). the SendRetry property defines the maximum number of retries after there is a failure in first attempt.


The Timeout property sets the timeout value in seconds which is used whenever the GSM Modem or Phone stops responding.

Init String Is used to send additionnal AT command to the modem during initializtion phase.
Messages Settings  
Option Description
Character Encoding
Dafault Alphabet 7-Bit Default GSM Character Encoding (Maximum 160 characters per message)
ANSI (8 bits) 8-Bit ANSI Character Encoding (Maximum 140 characters per message)
Unicode (16 bits) 16-Bit Unicode Character Encoding (Maximum 70 characters per message)

To have more details of the charactere encoding scheme refer to SMS Data Encoding Schema chapter

Oversized Message

As per GSM specifications, the maximum number of characters allowed in a single text message is dependent on the type of character encoding as given in Character Encoding option.

The Oversized Message property defines how a message is to be treated if it exceeds the maximum permissible length.

Truncate Truncates the outgoing text message to one message of length based on type of character encoding
Split Splits the message to multiple messages with each message length within the maximum size depending on character encoding
Formatted Split Same as SImple Split, except that this mode adds a page number to each split part of outgoing message at the end of the message
Concatenate Splits the outgoing message to multiple messages, which when received by the recipient, is displayed as one single message.
Alert Message Mode If checked then the message is displayed immediately on recipients mobile phone (Also known as Flash Message).


When the setting are completed you should perform the testing procedures.