This card can only output an MPEG transport stream at a bit rate useable for input to a 64QAM modulator. It does not support the higher MPEG transport steam bit rate which would be required for input to a 256QAM modulator.
Note: This Field Notice does not apply to the C6920-DHEI-I/O-C card.
During the original development of this card at V-Bits (a Cisco acquired company) an assumption was made that the clocking signal required to generate a DigiCable Headend Expansion Interface (DHEI) signal output at a rate required for use with 256 QAM modulators would be provided through the DHEI inputs from the satellite demodulators. This is not the case with current demodulators. Therefore the DHEI I/O card had to be re-engineered at Cisco to internally generate the appropriate clocking signals by the addition of an on-board crystal oscillator circuit.
This board will not function at 256QAM rates. The GUI will return a Parameter out of limits error if the user tries to use it in this mode.
There is no Workaround.
The solution is to RMA the C6920-DHEI-I/O card for a C6920-DHEI-I/O-C card.
How To Identify Hardware Levels
The external label ("DHEI I/O") does not indicate the difference between the two cards. Identification of cards on a running system can easily be checked by using the RateMUX GUI. Select the "Board" pull down option on the main screen, and inspect the revision number of the DHEI I/O card in question. If it returns "DHEI_IO_Rev2" or lower then it does not support QAM 256. If the DHEI I/O card is not in an active system then you can physically inspect the board and check for the presence of two on-board oscillators as indicated in the following picture:
For More Information
If you require further assistance, or if you have any further questions regarding this field notice, please contact the Cisco Systems Technical Assistance Center (TAC) by one of the following methods: