Distorted sound and garbled speech on a 5550

[Chaos77]

Got Distorted sound at random calls, and the speech is garbled to the point that you could not understand the caller anymore.
This on both 5550’s 

The consoles are setup with dual NIC, al works fine. NIC 1 is VoiceLAN NIC 2 DataLAN .
The Cables to the console and PC are separately, the switch function of the 5550 isn't used.

If a put a distorted call from the 5550 true to a 5320 phone then al distortion is gone.

Already did the following.

-   Replaced the pc, cables
-   Replaced all cables
-   Replaced one TKB for a new one.
-   Connected one 5550 directly on the switch, to rule out a part of the LAN.
-    Traced with wireshark at the switch of TKB, had distorted calls nothing OD to see in the trace.

Tomorrow I'm am going to hook up a TKB on a Mitel 3300 to upgrade the firmware. Don't think vMCD is upgrading the firmware right.
I am open for any suggestions regarding this weird and annoying problem.

[LoopyLou]

Not sure what you mean regarding dual NIC's? Assume you mean the PC the 5550 application is installed on. The dual NICS should make sure there is good communication between the 5550 software and the keypad. Unless I am very much mistaken the voice doesn't go through the PC it goes through the keypad. Therefore the key pad itself needs to be on the Voice VLAN or have the appropriate routing in place. It should also have a static reservation for its IP address in the 3300.

When it happens is there any particular type of call that it happens to? i.e do you ever get it calling directly from an IP phone to the console or is it only on incoming trunks calls. Is there anything unique regarding the calls that are bad?

[Chaos77]

Problem solved, Duplex mis match at the SIP trunk, Thats why it was one way and random.