Dear all,
I can decode 3 differents networks.
2 of them have gps information and it works good for me.
In TTT I have this :
Type:UDT-4 Length:84 Protocol:Location_information SubType:Short_location_report Lat:47,221298° Long:5,951092° Accuracy: less than 20m Velocity:0,0km/h Dir:0°
but on the third network I see this :
D_SDS_Data Party_SSI:10000000 Type:UDT-4 Length:17 Protocol:Location_information SubType:Location_protocol_with_extension SubTypeExt:Immediate_location_report_request ReportType:Short
but nothing else...
I checked on all other frequencies and no GPS data send over the air...
Any idea ?
Thanks in advance for your help
Nicolas
The 'third network' is only sending the request.
The MS could be responding on the uplink. It could then be passed back to the requester internal to the tetra infrastructure and not passed back to the downlink where we could see it. I guess it's the type of set-up that determines if it needs to be returned to the downlink.
Still thanks for a great software. I use a lot of time running it.
But one thing I am missing is a setting that can show encrypted calls.
When using old version 1.0.5.0 it shows a lot of ISSI on encrypted network.
And even when it says PDU is encrypted some ISSI is not encrypted.
I know that becouse I know the ISSI numbers they are using on the encrypted network.
Also I can se that the Carier it shows is out of scope so this tell that some of the PDU is encrypted
but not all of the PDU is.
My limited understanding of the standards about 'encryption mode' (PDU encryption) tells me that the address (SSI) is encrypted.
The standards also state "the address is encrypted
when appropriate" and point to rules in another document about when it is applied, but for the life of me I can't see any reference to it. Searching for 'address encryption' in the document only shows one reference in a Figure 4.26.
According to the standards EN300-392-02 - 21.4.3.1 MAC-RESOURCE
The encryption mode field shall indicate whether or not the TM-SDU contents are encrypted and, if so, the encryption
algorithm used. The MAC header shall not be encrypted except that, if the encryption mode field is not set to 002:
• the channel allocation element (when present) shall be encrypted; and
• the address is encrypted when appropriate (for details of the address encryption method and when it is used,
see ETSI EN 300 392-7 [8]).
NOTE 1: In the case of an event label assignment or usage marker assignment, the address element comprises two
parts (SSI or SMI and event label or usage marker). The rules defined in ETSI EN 300 392-7 [8] for when
address encryption is used apply independently to each part of the address.
In an older version of the standards, it refers to the encrypted address as 'alias stream':
MAC header may be encrypted and an alias stream may be
used to encrypt the address.
And also why have Network Info Header Encrypted when all calls only says Clear.
In never version I have never seen an encrypted call.
Your right, there is probably no need for this column.
It's not likely that a call will have clear PDUs and encrypted speech. Although it's possible.
There are 3 flags in different places (protocols) that indicate encryption.
- Encryption mode - in MAC (PDU encryption)
- Encryption control - in CMCE (E2EE)
- Encryption flag - in CMCE (Tetra E2EE for circuit mode speech or data)
The last two can not be determined if 1st one is used.
This excludes the SYSINFO 'Security information element' which only tells if encryption is supported on network (Security Class 2-3)
I could output the SSI with the encrypted PDU message, but there is no guarantee that the SSI shown is correct.
No entry can be added to calls list because if the PDU is encrypted then this means the call control PDUs are encrypted.
Latest version (v1.0.15.10) can be found here: Release post