Owners Guide

yup…. it's here https://www.flexradio.com/documentation/maestro-user-guide-pdf/

If the link doesn't work properly for you, just to to flexradio.com, then select 'Suppot', then 'Documentation' and from the Category drop down, select 'User Guides'. It'll show up in the list.

It's not specifically for the Maestro C, but it will describe all of the features of the Maestro….

@Mike… it looks like you attached two copies of the User Guide….

Yup… it's a bit weird for us old guys who are used to the sleeve ALWAYS being common/ground, but that's the new standard….

As it notes in Blue, the CTIA is now the standard for most earphones/TRRS headphone plugs. Exerpt from Wikipedia:

"TRRS standards

Two different forms are frequently found, both of which place left audio on the tip and right audio on the first ring (for compatibility with stereo connectors). Where they differ is in the placement of the microphone and return contacts.

The first, which places the ground return on the sleeve and the microphone on the second ring, is standardized in OMTP and has been accepted as a national Chinese standard YDT 1885–2009. It is mostly used on older devices, such as older Nokia mobiles, older Samsung smartphones, and some Sony Ericsson phones, and products meant for the Chinese market.Headsets using this wiring may be indicated by black plastic separators between the rings.

The second, which reverses these contacts, with the microphone on the sleeve, is used by Apple's iPhone line until the 6S and SE (1st), and has become the de facto TRRS standard, to maintain compatibility with these products.It is now used by HTC devices, recent Samsung, Nokia, and Sony phones, among others. This is referred to as CTIA/AHJ, and has the disadvantage that the mic will be shorted to ground if the body of the device is metal, and the sleeve has a flange that contacts it. Headsets using this wiring may sometimes be indicated by white plastic separators between the rings."