There appears to be either a firmware bug or a hardware defect with this cable. Steps to reproduce: 1) Pair the cable with a mac computer and a mobile phone. I used a macbook pro and an iphone 8. 2) Connect the cable on the iphone. 3) Connect the cable on the computer and start some kind of voice call where the microphone is used, eg zoom, google hangouts, skype etc. You will find that the cable repeatedly connects and disconnects on the phone causing the "Connected" sound clip to repeatedly play through the headphones. This is because the use of the microphone on the mac forces the Shure cable to use the SCO codec, which it apparently has problems with. Workround: In the sound preferences on the mac, set the input to the internal microphone. This lets the Shure cable use the AAC codec and then all is well. I have reported this issue to Shure and await their findings.