Overview

You may notice an issue on your SMSC where the special character "@" conversion is not working properly in AO-MT Routing.

Solution

This issue may be caused because the Data Coding Scheme (DCS) in the AO rule is set to "Unknown":

SMPP Data Coding Scheme: Unknown (0x11).

This behavior is not expected by the SMSC so the proper Character Set Conversion table is not applied. For the @ special character, the expected DCS is:
SMPP Data Coding Scheme: SMSC default alphabet (0x00)

From the HUB Operator Manual -
3.12 Character Set Conversion
The HUB support for configurable character set conversion allows message data conversion between applications and SMSCs. It is possible to provision AO and AT conversion tables in applications and SMSCs. These tables define the mapping to and from an external format to the default GSM alphabet. The conversion is applied to text messages, and not to binary messages. Messages from applications and SMSC are passed via the HUB to the RTR. The HUB insures that all messages from the applications or SMSCs are converted to the default GSM character set.

To fix this issue, you will have to change the DCS settings of the AO rule. To do so:

In the MGR GUI, navigate to Routing > Routing Rules > AOR
Select the Application/AOR that is having issues with the special character @ conversion. Scroll down to the field DCS [cond] and from the dropdown menu, select Byte Value (00-FF). A text box will appear to the right, in this enter the value 00.
Scroll down and click on Save:
If you have issues with any other special characters, please replace the 00 in Step 2 above with the equivalent GSM 7-bit default alphabet (Hexadecimal) code found in this conversion table: GSM 7-bit Default Alphabet Table.