- the release of a held call when a waiting call exists,
- or the release of a particular party in a held
- multiparty call.
-
- Note that releasing a held call or a particular party
- of a held multiparty call might not be possible on some
- implementations.
+ the release of a held call when a waiting call exists.
+ This is because 27.007 allows CHLD=1X to operate only
+ on active calls. Hence a held call cannot be hung up
+ without affecting the state of the incoming call (e.g.
+ using other CHLD alternatives). Most manufacturers
+ provide vendor extensions that do allow the state of
+ the held call to be modified using CHLD=1X or
+ equivalent. It should be noted that Bluetooth HFP
+ specifies the classic 27.007 behavior and does not
+ allow CHLD=1X to modify the state of held calls.
+
+ Based on the discussion above, it should also be noted
+ that releasing a particular party of a held multiparty
+ call might not be possible on some implementations.
+ It is recommended for the applications to structure
+ their UI accordingly.