Edward via tde-users wrote:

> I have Bluetooth Manager (blueman) installed, with ofono for HFP/HSP.
> 
> My thought was that the electronics in the Sentry models perhaps did not
> support HFP/HSP.
> 

In the gnome/gtk/python app I guess there might be issue with some hardware
and the so called profiles. IF profile is not advertised, it would not
connect or I read that in some cases the order matters, besides BT and PA
keep record which device used which profile.
Sometime it is better to remove the pairing and pair+connect again.

I would be surprised if headphones would have a microphone and do not
support HSP. Often these HFP/HSP are mixed, but they are different however
at the bottom it is the same - you have a speaker and microphone and
bidirectional audio stream. HFP is for mobiles while HSP for head sets.

You could easily scan the device for what is supported:

[bluetooth]# devices
[bluetooth]# info (MAC of device)
[...]
        UUID: Headset AG               
(00001112-0000-1000-8000-00805f9b34fb)
        UUID: Handsfree Audio Gateway  
(0000111f-0000-1000-8000-00805f9b34fb)
[...]

> I subsequently tested an older LG Tone and found that also works with
> HFP/HSP.

I guess you already connected with A2DP and now it might be the profile of
choice for this device unless it is something else we don't know now, but
if it had a mic it should support also the HSP.

you could also easily (or may be not so easily) connect and disconnect via
DBUS methods

dbus-send --system --print-reply --dest=org.bluez /org/bluez/hci0/dev_00_01_02_03_04_05
org.bluez.Device1.Connect

and look behind the scene what happens

dbus-monitor --system