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DMV-A Routing/Unrouting failure - 0x280ee error

Symptom:
Using DMV-A boards, a user will experience no audio when routing and unrouting occur in a specific sequences.   Upon inspection of the RTF logs, the “280ee” error is seen indicating that a problem has occurred while attempting to route/unroute network and voice resources. Typically with these errors, no indication is give to the application that an error has occurred – rather the listen and unlisten functions will return successful but the audio path will NOT be connected correctly.

What to look for:

dm3low DEBG Dm3Timeslot dtiB1T2 <---- QResultError (0x2813a) (So1:UnlistenUnroute) 
dm3low ERR1 Dm3Timeslot dtiB1T2 <---- QResultError(0x2813a) failedFunction=0x6 - failedError=0x280ee : Listen failed(So1:UnlistenUnroute)

The Problem Explained: 
Three scenarios describe this problem:
1- A quick execution of gc_Listen( ), dx_listen( ) to the same time slot, followed by dx_unlisten( ) and gc_UnListen( ) 
2- OR incorrectly routing and unrouting of the network and voice resources to the same time slot 
3- When an application issues a listen on a voice timeslot, and then issues a listen on the same timeslot of the network resource.  Internally the routing uses the same Mediastream Management ASIC (MMA) timeslot, a procedure called Sharing Of Timeslots (SOT).

The DMV-A network boards utilize an algorithm called Sharing Of Timeslots (SOT). The SOT algorithm states that an internal (on the local switching device) TDM timeslot will be shared between the network resource and the voice resource if both want to listen to the same external CT Bus timeslot and the network resource performed a listen prior to the voice resource performing an listen. 

The algorithm was developed in order to maximize the efficiency of the internal timeslots used for transmit (external) reference. The SOT algorithm places restrictions on the order in which an application must listen and unlisten its network and media resources - by design requiring that timeslots be unrouted in reverse order they were routed in at the firmware level which is documented as a permanent restriction in the SR 6.0 Release Update Guide (IPY00031563 / PTR36612).

Workaround: 
When the application is done listening with the voice and network device, it MUST unroute both the voice and network device in the opposite order they were routed to free up that timeslot for future use. In addition, when calling unlisten, the application should implement a guard time (i.e., sleep) of 100 msec if listen has been called for the same time slot to insure that the functions reach the firmware in the correct order (note: calling unlisten( ) for a different time slot does not require the guard time.) The application MUST still unroute time slots in reverse order. 

Note that the sharing of timeslot algorithm is only used on DMV-A network boards.  Later DM3 models, i.e. DMV-B does not use this algorithm.

Example:
Incorrect (280ee error): gc_listen – dx_listen – gc_unlisten – dx_unlisten
Correct: gc_listen – dx_listen – dx_unlisten – gc_unlisten

Product List:
DMV-A boards
Note: DMV-B boards do NOT support SOT – therefore will NOT experience this problem.

Glossary of Acronyms / Terms
SOT – Sharing of Timeslots


Related Documentation
 http://www.dialogic.com/support/helpweb/dxall/tnotes/legacy/2000/tn043.htm

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