If you change MRG's you wont affect the ability to dial 911 calls.
The only way you could effect the ability to dial 911 was if you were to create an extension or translation pattern 911 as these matches would take priority over a dial pattern.
Best thing to do is make a note of the current settings, make the changes you feel you need to and then test dialling 911. If the call is successful explain to the emergency operator that you have installed a new telephone system and are just ensuring dialling emergency services works and if it doesnt work reinstate the original configuration.
I would recommend that you call your local police on their non-emergency number to schedule a test. That way when you do call they know they don't have to dispatch a police cruiser if by some unhappy chance you get a connection with one-way voice.
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The short answer is that you don't.... That isn't entirely true while at
the same time it kind of is, but for the most part you don't configure
the softkeys. You enable or disable them via TCL. Here is the long
answer. Be sure to read the whole thing or e...
Topology: IP Phone > Switches > Microsoft NPS setup to forward 802.1x
proxy to > ISE 2.1 patch 3 Authentication: EAP-TLS using Cisco MIC SANs
Phone Models 802.1X support? 802.1x flavor Addtl Comment EAP-MD5 EAP-TLS
Cisco 3905 Y Y N Cisco 6911 Y Y N Cisco ...