Thanks again, Mitch. FYI I went back to using a direct wired ethernet connection to my home router when I couldn't initially re-establish connectivity via the network bridge. So all my earlier t-shooting efforts were done without the network bridge. I do have a cheapo wi-fi extender (IOGear GWU627) that used to work with a blu-ray player; unfortunately, like so many of these extenders, it has failed and no longer works ;-). They all seem to get mediocre reviews but I'll give try another brand and hope for the best.
The tones I hear are the 3 note sequence that repeats 3 times; it is not a busy signal.
For the avoidance of any doubt, here are the status pages for both units (including the Control unit before and after a connect attempt). I admit the details are beyond my current knowledge level, so there could be something below that I didn't recognize as incorrect, or that flags the cause of the problem.
RADIO:
Status
Radio ON
Connection status Disconnected
SIP status Idle
Last SIP error None
RTP/UDP audio status Disconnected
UDP cmd status Disconnected
SIP command timeout 0
Rx Jitter buffer size 12
Rx Jitter delay 10
Dual Rx 0
External IP 206.146.83.22
SIP Out port 13000
SIP In port 13000
Audio Out port 0
Audio In port 0
Command Out port 0
Command In port 13002
External SIP In port 13000
External Audio In port 13001
External Cmd In port 13002
Other party 0.0.0.0
Input 1 High
Input 2 High
Output 0 Low
Output 1 Low
Output 2 Low
Dynamic DNS status
OK
Ping status (watchdog) Off
DNS status OK, remoterig.com = 213.180.92.125
Active profile Default
PTT status OFF
Antenna-Switch (IP) not connected
Common network settings No
CONTROL before connect attempt:
Status
Control panel ON
Radio OFF
Connection status Disconnected
SIP status Idle
Last SIP error None
RTP/UDP audio status Disconnected
UDP cmd status Disconnected
SIP command timeout 0
Rx Jitter buffer size 12
Rx Jitter delay 10
Dual Rx 0
SIP Out port 13000
SIP In port 13000
Audio Out port 0
Audio In port 0
Command Out port 0
Command In port 13002
External SIP In port 13000
External Audio In port 13001
External Cmd In port 13002
Other party 0.0.0.0
Input 0 High
Input 1 High
Input 2 High
Output 0 Low
Output 1 Low
Output 2 Low
DNS status OK, rkfe6qsh.ddns.remoterig.com = 206.146.83.22
Active profile: Default
PTT status:
CONTROL after start attempt (status page didn't dynamically refresh. I went to another page and then back to Status):
Status
Control panel ON
Radio OFF
Connection status Disconnected
SIP status Error
Last SIP error SIP Error
RTP/UDP audio status Disconnected
UDP cmd status Disconnected
SIP command timeout 0
Rx Jitter buffer size 12
Rx Jitter delay 10
Dual Rx 0
SIP Out port 13000
SIP In port 13000
Audio Out port 0
Audio In port 0
Command Out port 0
Command In port 13002
External SIP In port 13000
External Audio In port 13001
External Cmd In port 13002
Other party 206.146.83.22
Input 0 High
Input 1 High
Input 2 High
Output 0 Low
Output 1 Low
Output 2 Low
DNS status OK, rkfe6qsh.ddns.remoterig.com = 206.146.83.22
Active profile: Default
PTT status: OFF