Looking into this further I have found a possible workaround:
When sending an SMS of more than 160 Characters, the user gets multiple messages. What can be done so that only one message is sent to client?
Try the following:
upgrade to v1.51.28,
Link:
https://webfiles.multitech.com/engineering/unofficial-releases/iSMS%20(Formerly%20SMSFinder)/Firmware/SF100/1.51.28/
once upgraded:
enable “Enable PDU Mode” and “Concatenate Multipart Outbound Messages” in the SMS Settings menu.
The SMS standard limit is 160 characters so what you are seeing is normal. The SF100-g won’t be able to merge this into a single text due to the standard it follows, but the receiving side may be able to reconstruct the text back to the original using the tags (1of7..etc).
You can give our customer service a call to order one. They can be reached at 1-888-288-5470. Have your serial number available in case it is needed.