SMPP Service

In SMPP (Short Message Peer-to-Peer) protocol, the “Charset” parameter is used to specify the character set or encoding scheme to be used for the text of a Short Message (SMS) being sent or received. The character set determines how the characters of the text message are represented in binary format before being transmitted over the SMPP connection.

• GSM 03.38 Character Set (GSM):

• Also known as the GSM 7-bit default alphabet.

• This character set is used for simple text messages that include standard alphanumeric characters, numbers, a limited set of symbols, and some special characters commonly used in the GSM (Global System for Mobile Communications) network.

• The GSM 03.38 character set allows for the transmission of up to 160 characters in a single SMS.

• ASCII Character Set:

• The ASCII (American Standard Code for Information Interchange) character set is used for basic text messages containing standard English alphanumeric characters, numbers, punctuation marks, and a limited set of symbols.

• Like the GSM 03.38 character set, the ASCII character set allows for the transmission of up to 160 characters in a single SMS.

• UCS-2 (Unicode) Character Set:

• This character set is used when SMS messages need to include characters not available in the GSM 03.38 or ASCII character sets.

• UCS-2 uses 16 bits per character and can encode a much broader range of characters, including non-Latin scripts, emojis, and other international characters.

• UCS-2 can transmit up to 70 characters in a single SMS.

Regarding the number of character sets in SMPP, the SMPP protocol itself does not define a specific limit on the number of character sets that can be supported. However, in practical implementations, SMPP clients and servers typically support the character sets mentioned above (GSM 03.38, ASCII, and UCS-2) as they are the most commonly used for SMS messaging.

The choice of character set depends on the content of the message. Simple text messages with standard alphanumeric characters and some symbols can use either the GSM 03.38 or ASCII character set. If the message contains characters outside these character sets, such as non-Latin characters or emojis, the UCS-2 character set is required to preserve the integrity of the content.

SMPP implementations need to ensure that both the sender and receiver agree on the character set being used to properly encode and decode the text messages during SMS communication.