Trying to connect it to a  Cardo PackTalk system.

They have been paired by: putting the Sena into Universal Intercom pairing.  And the Pack Talk by putting it into Pair Bluetooth Device.

They have paired ok.

 If I open up a conversation to the Pack Talk by pressing my ‘front button’ on the remote control, the link opens and works correctly.  I then close this link by pressing the ‘front button’ again.

 However, if the PackTalk user opens a link to the Sena by pressing the  ‘start a phone call’, the link works (I get a message in my Sena saying “phone connected”), and I can here my friend for about 5 seconds before he automatically gets cut off.

Ive tried doing nothing on the Sena when I get the “phone connected” message, and I’ve also tried pressing the back or front buttons on the remote to ‘accept’ the call, but this made no difference.