Plantronics update for MOC headsets

After talking to Plantronics tech support, regarding the MOC headsets, we learned the following:

HW251N-USB (discontinued) – The same as the one below but not MOC certified – QD and hardwired versions.

HW251N/DA (digital audio) M (Microsoft) – Single ear with QD feature – MOC certified, has the firmware to default to MOC plug & play and compatible with their hookswitch capability.
HW261N/DA M – Same as above but two ear model.

HW111N USB M – The less expensive version of the ones above – Single ear, no QD – MOC certified
HW121N USB M – Same, dual ear

Plantronics  said the headsets above that are MOC certified loose their hookswitch capabilities on non-MOC software. The reverse is true for applications such as the DA45/H251N. With the persono suite and regular softphone software the hookswitch feature is supported but that is lost on MOC applications.

DA261N and DA261N USB – “D” signifies that these are true stereo headsets. The USB model does not support hookswitch.