Hi,
I develop a new version of a product with EG915U-EU modem that replaced the M95FB (previously used with a great success).
The EG915 module connects to LTE network, sends and receives SMS without any problems, looks allright.
In the “EC200U&EG915U_Series_AT_Commands_Manual” we can find that it also should support USSD operations (AT+CUSD command, page 186).
However, when I send the USSD request, the response appears as some raw binary data with unknown encoding:
- when my MCU sends the request:
AT+CUSD=1,"101#" - no “OK” response is returned from the module,
- 11 seconds later, here comes the following result code, with some sort of binary data:
+CUSD: 2, "Y^UadT:bfMX2r@$“$Z9 =#aD]0lR” ,0
What is the coding scheme of this data? Shouldn’t it be in 7-bit ASCII encoding?
The previous module (M95FB) with the same SIM card, always returns, to the same request, a human-readable, plain ASCII string in +CUSD result code, exactly as it is displayed in a mobile phone.
In the EG915U manual (page 188) we can only find one sentence regarding the USSD result code:
For an USSD response from the network, or a network-initiated operation, the format is: +CUSD: status[,rspstr, [dcs]].
where:
rspstr String type. Unstructured Supplementary Service Data (USSD) received from the network.
… but rspstr= "Y^UadT:bfMX2r@$“$Z9 =#aD]0lR” does not look like a string,
and also dcs=0 looks weird and makes no sense (German language, according to 3GPP TS 23.038 ? - not possible in my network and location).
Best regards,
Pablo