It will be better to test the DSP since some of the symptoms than can be attributed to DSP hardware or software issues are no audio heard, or dead air on the voice path after the call is connected.That usually result in a call setup failure. Here is the document that will help in testing the DSP.
Are you getting this error “Installer User Interface Mode Not Supported. The installer cannot run in this UI mode. To specify the interface mode, use the -i command-line option, followed by the UI mode identifier. The value UI mode identifiers...
The below trick might come handy when you have to add a new node to a cluster but you don't have or is unsure of the security password for the publisher. This procedure has been around for ages.
1) Login into the CLI of the Publisher.