Depends on many factors. First be sure you are running a reliable and non-beta version of IOS, and the latest version in the train of IOS that you are running. So if you are on 12.1 mainline be sure you are on 12.1.15 which is the latest. Second, check the port stats. If there is no call up, 'show voice port summary' on 3810 should show IDLE state for the ports, see below:
PORT SIG-TYPE ADMIN OPER IN-STATUS OUT-STATUS CODEC VAD GAIN ATTN CANCEL
1/1 fxs-ls up up on-hook idle 729ar8 n 0 3 y
1/2 fxs-ls up up on-hook idle 729ar8 n 0 3 y
So if your ports show "hung" or "off-hook" when there is no active call, then try to RESET the port.
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.