Technically, a binary SMS is actually an XML-formatted text SMS made up of up to 140 bytes of data. This data is split into two distinct parts – the user data header (UDH) and the message data. UDH notifies mobile phones about the type of data in the message, defining the type of content being sent.
How do I send a binary SMS? (for developers)
To send a binary message, you need to specify in your request:
type — Set to “binary”
content — The binary content in hexadecimal
udh — Include if your message has a User Data Header