I was doing the exact same thing earlier this year as a prelude to a paging setup I never finished.
The above commands tell Phone1 to send an RTP stream and Phone2 to receive it. Your description of the phone response sounds backwards as the mute button is coming up on phone 2. By default when you issue a RTPTx command to the phone it comes up muted. I assume this is a security feature to prevent eavesdropping.
You might try finding a freeware tool called RAT. I used it to send/receive G711 streams to my phone.
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.