Thanks for clarifying a lot of this!

So... using DISA securely requires an unused, dedicated channel ...which basically counts it out for this customer.

If I'm understanding all of this correctly... if I leave the DID I assigned to DISA in place and remove the security code from the trunk, then I should still be able to dial-in to DISA and enter 359 to do some remote programming.

Is anything else required?

It seems like I'm in the system, but as soon as I enter the password for the extension I'm trying to change I hear 5 tones, whereas every other time I hear two tones. I take it that 5 tones means something is off... because it seems to go downhill from there.

I'll try on-site as you've suggested.

It doesn't seem viable for the end-user. But, it would be nice to have available for emergency use.

Otherwise... I can access DB Studio remotely via terminal server... is there a way to forward or unforward a DID from there if I had to do it in a pinch?