Is it possible to tell Call Manager Express (CUCME 8.6) to set the same phone type 7911G -- to make one ephone SCCP for internal lines and SIP for external lines? I can imagine the following issues:
Either way I would enjoy some input as I have multiple remote workers and I would love to put phones on their desks just not with VPN.
You will not have good results trying to register the phone directly to a public address, on reason is that would expose you CME to SIP from outside, not a good idea.
To use a phone with CME from a remote location, setup a proper VPN, and everything will run smooth and secure.
You don't need the phone to be in SIP mode to use a SIP trunk with CME.
And VPN overhead is not too much once it provides you with features a security.