Specifications

Chapter 9 – Supplementary Service Commands
Multi-Tech Systems, Inc. AT Commands for EDGE Modems (S000371B) 120
9.14 AT+CUSD Supplementary Service
Notifications
Description: This command allows control of the Unstructured Supplementary Service Data (USSD).
Both network and mobile initiated operations are supported.
Test Command Syntax: AT+CUSD=?
Response: +CUSD: (list of supported<n>s)
OK
Read Command Syntax: AT+CUSD? The read command returns the current <n> value.
Response: +CUSD: <n>
OK
Write Command Syntax: AT+CUSD=<n>[, <str>[, <dcs>]]
The write command parameter <n> is used to disable/enable the presentation of an
unsolicited result code (USSD response from the network, or network initiated operation)
“+CUSD: <m>[<str>[<dcs>]]” to the TE.
When <str> is given, a mobile initiated USSD string or a response USSD string to a
network initiated operation is sent to the network. The response USSD string from the
network is returned in a subsequent unsolicited result code “+CUSD”
Response: OK
+CME ERROR
Parameter Descriptions:
<n>
0 Disable the result code presentation in the TA. Default.
1 Enable the result code presentation in the TA
2 Cancel session (not applicable to read command response)
<str>
String type USSD-string (when <str> parameter is not given, network is not interrogated).
If <dcs> indicates that GSM 03.38 default alphabet is used, TA converts GSM alphabet into current TE character
set according to rules of GSM 07.05 Annex A.
<dcs>
GSM 03.38 Cell Broadcast Data Coding Scheme in integer format (default 15).
<m>
0 No further user action required (network initiated USSD-Notify, or no further information needed
after mobile initiated operation)
1 Further user action required (network initiated USSD-Request, or further information needed
after mobile initiated operation).
If <m>=1, then the URC ends with “>” to prompt the user for input. The user action is finished
with <CTRL-Z> or aborted with <ESC>.
2 USSD terminated by network.
Unsolicited Result Code:
+CUSD: <m>[<str>[<dcs>]]
URC “+CUSD” indicates an USSD response from the network, or network initiated operation.
Notes:
• For the write command, only <dcs>= 15 is supported.
• When a USSD string is sent via ATD, a “AT+CUSD=1” is executed implicitly.
• It is recommended to finalize or escape a pending USSD user interaction before further actions are done to
prevent blocking situations.