Why are more SMS deducted from my account than actually sent?

Short answer:

SMS messages are technically divided into segments.
If non‑standard characters such as ä, ö, ü or other special characters are used, a message requires more segments, even though it appears as a single SMS to the recipient. As a result, multiple SMS are charged.

Each message sent by the system always consists of:

• the device name
• the notification text
• a timestamp (YYYY‑MM‑DD HH:MM:SS)

These elements further increase the total message length.

Solution:

• Avoid special characters and replace non‑standard letters
• Keep texts and/or device names short

Detailed explanation (for those interested):

SMS messages are not always transmitted as a single message. If necessary, they are split into multiple segments.

A single SMS can contain up to 140 bytes of user data.
The number of characters depends on the encoding used:

• GSM standard alphabet (3GPP 23.038): 7 bits per character → up to 160 characters
• UCS‑2 (for special characters): 16 bits per character → max. 70 characters per segment

If this limit is exceeded, the message is split into multiple concatenated segments. They appear as a single message to the recipient but are technically transmitted separately and counted individually.

Additionally, each message sent by the IoT portal or CMS device always contains:

• the device name
• the notification text
• the timestamp

These fixed elements reduce the available space for the actual message text, making segmentation more likely.