I looked through the supported device table for RME 3.5 and RME 4.0.5 and see where the VG248 Voice Gateways are not supported.
I also see where these devices are menu driven thus not IOS based. Does anyone know of a way to back the configurations up on these devices?
No, there is no RME support for these devices, except for basic mibII. That is not likely to change. Backing up the config is not very friendly, but here's how:
1) Telnet to the VG248 device via a terminal program (Hyperterm on Windows is best, and a telnet out of xterm works best on X).
2) Go to Diagnostics --> Show configuration
3) Log the output provided (using your terminal program) by "show configuration" and copy it to a file and name the file as "user.cfg"
You can also FTP to the VG248, and FTP the user.cfg directly from it instead of capturing the telnet session.
To restore the config:
1) Then FTP to the VG248 device and upload the "user.cfg" file.