If ‘Enable Live DialPad’ is set to ‘Yes’, the EHS function with Plantronics CS500 with APD-80 (incl. 85638-01 cable) is messed up:
If you hang up the call, the EHS headset hangs up shortly and is 1 sec. later on-line again. Doesn’t matter if you use the button on the GRP2614 or on the headset.
This issue occurs only in conjunction with this setting. It took some time to find out, because it doesn’t make sense at all.