Specifications

Chapter 9 – Supplementary Service Commands
Multi-Tech Systems, Inc. AT Commands for EDGE (E1) Modems (S000474A) 144
9.14 AT+CUSD Unstructured Supplementary Service Data
Description: This command allows control of the Unstructured Supplementary Service Data (USSD). Both
network and mobile initiated operations are supported.
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_urc>[<dcs>]]" to
the TE.
When parameter <str_write> 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"
Syntax: Test Command: AT+CUSD=?
Response: +CUSD: (list of supported<n>s)
OK
Read Command: AT+CUSD?
Response: +CUSD: <n>
OK
Write Command: AT+CUSD=<n>[, <str>[, <dcs>]]
Response: OK
ERROR
+CME ERROR: <err>
Unsolicited Result Code:
+CUSD: <m>[<str>[<dcs>]]
URC “+CUSD” indicates an USSD response from the network, or network initiated operation.
Parameters:
<n>
0 Disable the result code presentation in the TA. Default (This is the factory default value and can
be restored to '0' with AT&F).
1 Enable the result code presentation in the TA
2 Cancel session (not applicable to read command response)
<str_write> String type USSD-string (when <str_write> parameter is not given, network is not interrogated).
For the write command, only <dcs>= 15 is supported.
<str_urc> String type USSD-string .
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. Otherwise in case of invalid
or omitted <dcs> conversion of <str_urc> is not possible.
<dcs> GSM 03.38 Cell Broadcast Data Coding Scheme in integer format (default 15).
In case of an
invalid or omitted <dcs> from the network side (MT), <dcs> will not be given out.
<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.
4 Operation not supported.
5 Network time out.
Notes:
• 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.
• This command is PIN protected.
• This command is not supported in airplane mode.