I try to keep this simple, so it’s maybe not 100% accurate but hopefully give you an idea about call control agent and dial plan
call control agent
Simply explained the Server who knows every phone and the dial plan of them.
All Cisco Phones are designed to work with a cisco call control agent (Like Cisco unified Communications Manager) Since you have a Cisco 3945 router I guess you're using Cisco Unified Communications Manager Express. (on which your Phone is registered) Can you confirm this? (do a "show telephony-service" on your Router) you may post a full config here. Keep in mind to remove sensitive data before posting.
Simply explained this is list of which phone gets which number. Additionally there are entries for Numbers outside your Organization. (because this numbers have to be routed through a T1 link, SIP Trunk or maybe even analog line)
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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 ...