3CX + W60B + W56H

[Babylonia]

I did some testing here.
In my situation I do use desk phones T41S as a stand alone telephone, with its own “local” SIP-accounts (internal used number).

Also using the W60B DECT base station with in my case at this moment just two hand sets.
The base station do have its own own “local” SIP-account (internal used number),
in the same way as the desk phones T41S.

But as for the desk phones T41S a SIP account is only used for one phone, the SIP account for a W60B DECT base station is used for all individual hand sets.

So redirect a call form one hand set, to another hand set is done by another way, than redirection of a call to a stand alone desk phone.

Redirection from a call from one hand set to another hand set,
I got the same experience as you, that the “ended” call of the first hand set is not ringing, by coming in other calls as long as the conversation is active to the other hand set.

But in the case when I make a redirection from a W56H hand set tot a desk phone T41S, new calls, are coming in to all W56H hand sets, as well as an “interruption” call to the T41S phone that has taken over the redirection call more early.

Also when I make a redirection from a desk phone T41S to the W60B DECT base station, and one of the hand sets is taking over the call (and ending up the call by the T41S).
New calls are coming in to all phones and W56H hand sets.
The one hand set that is still active and took the redirected call more early, also do get an an “interruption” ring, as a new call is coming in.