DSDPlus DSD+ Fastlane: Message UNHANDLED IMPLICIT OPCODE

[paparazzo]

Hi,

while monitoring different P25 frequencys i often see the following message:
UNHANDLED IMPLICIT OPCODE: #40 0020A2017D222470

Can one please tell me what that mean?

 

[boatbod]

Hi,

while monitoring different P25 frequencys i often see the following message:
UNHANDLED IMPLICIT OPCODE: #40 0020A2017D222470

Can one please tell me what that mean?

Implicit/Explicit refers to the formatting of a tsbk/pdu and whether it contains just a channel number or the full transmit & receive frequency information.
Unhandled likely means DSD+ doesn't have any specific handling for that particular opcode.
In other words DSD+ is saying it received a short-form opcode and doesn't decode it any further.

 

[slicerwizard]

Implicit/Explicit refers to the formatting of a tsbk/pdu and whether it contains just a channel number or the full transmit & receive frequency information.

No, I see this "unhandled" notation on DSD+ link control word decoding/display, not on control channel TSBKs or PDUs. For LCW messages, implicit/explicit refers to whether these messages contain an MFID field/value. Implicit = MFID 0 (standard MFID) is implied. Explicit = MFID is present as an 8 bit value.

 

[boatbod]

As slicerwizard correctly observed, this has to be a LCW since it is too short for a TSBK. Opcode 0x40 would be Implicit Group Voice Channel User with svcopt=0x20, s=0, ga=0x017D, sa=0x222470.

 

[slicerwizard]

It can't be 0x40. That's 7 bits. LCW opcodes are only 6 bits. I think it's opcode 40, RFSS Status Broadcast - Explicit.

00   LRA
20A2 RX Ch
01   RFSS
7D   Site#
2224 TX Ch
70   SSC

 

[boatbod]

It can't be 0x40. That's 7 bits. LCW opcodes are only 6 bits. I think it's opcode 40, RFSS Status Broadcast - Explicit.

00   LRA
20A2 RX Ch
01   RFSS
7D   Site#
2224 TX Ch
70   SSC

Yes, I know the opcode is only 6 bits with the implicit/explicit bit being next, but doesn't it really whether DSD+ is masking the opcode or simply reporting the whole first octet as well as decimal vs hex? If it's not masking and reporting in hex then it's opcode 0x00, otherwise if it's masking and reporting in decimal then opcode 0x24 fits.