Some users have noted that the discussion of optimal connections for iPods in the MME documentation is not as clear as 
might be. I've revised the docs iwththe information below, which I hope is clear:

To check it an iPod is using the optimal available connections, you can examine the capabilities field for the device in
 the mediastores table:

Check for the capability MME_MSCAP_CONNECTION_NONOPTIMAL to determine if the iPod is using a USB (1-wire) or a serial (2
-wire) connection for control. MME_MSCAP_CONNECTION_NONOPTIMAL is set if it a serial (non-USB) connection is used for 
control.

Check for the capability MME_MSCAP_AUDIO_NONOPTIMAL to determine if the iPod is using an analog or digital audio 
connection. MME_MSCAP_AUDIO_NONOPTIMAL is set if an analog audio connection is being used.

Note that the MME_MSCAP_*_NONOPTIMAL flags apply only to iPods that are capable of playback and control via USB 
connections as well as serial and analog connections. For early iPods models, which only support serial and analog 
connections, a 2-wire connection is “optimal”, as it is the only one possible.