Helixnet: No talk path from a HBP-2X beltpack when using headset

Customer; No audio comes from a HBP-2X when a certain headset is connected to it.
When the same headset is connected to HRM, HKB, HMS and other devices, the headset works fine.
When a headset of a different type is connected to the HBP-2X, the beltpack works fine.

Solution; The HBP-2X has a detection mechanism (on pin 4 only) that detects if a headset is connected to the beltpack.
If no load is detected on pin 4, the beltpack will not pass audio from the headset mic to the rest of the system (however I believe the local sidetone will be heard).
In the HBP-2X’s hidden menu (10 sec hold on the BP Menu key) there is a way to ENABLE the HS SENSE BYPASS. This will bypass the detection mechanism.
This can bite you if you have a HBP-2XS (5 pin) if a single ear headset is wired between pins 3 and 5 (4 floating).

Edit: If you use a Shure BRH440M 4-pin XLR type headset with a headphone impedance of 37 Ω you will see that exact issue. Solution is setting HS SENSE BYPASS to ENABLED. That will fix that issue.