Some simple/simplistic thoughts/questions...

Has the DAC been used successfully prior to this?

Do you have another HP ProCurve 10-GbE SFP+ 7m Direct Attach Cable (J9285B) to try?

There's a transceiver and presumably an EEPROM at both ends of a DAC right?  If 
the EEPROM at one end were "bad" might the 57711 be happier with the other end 
of the DAC?  Getting some sort of error message at the switch side, which may 
(or may not) have more detailed diagnostics might help.

rick jones
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