The Engineering team found issues with adding telephones into PLs – they would cause dialing problems.
The ability to add telephone members to partylines has been removed.
Here is a workaround:
Create a Route from the Telephone to the PL, make it bidirectional (talk and reverse listen).
Create a Control.
Add the Route to the Control.
Test the control on a panel. You should see Diagnostic > Crosspoint Map crosspoints made from the telephone to anyone listening on the partyline.
Make it always trigger by doing Configuration >Logic > New.
Drag on a Latch, and a Control Output (O/P). Connect to the /Q (q-bar, normally closed) to the Control O/P and then add the new control into the O/P control area.