I have a CME directly connected to the Internet by a public IP address.
I have an ATA186 and elsewhere also connected to the Internet through a broadband phone with an analog. The ATA186 is registered without problems at the CME, but when a call is made the phone make ring but no audio traffic.
Sounds like you have the one way audio problem, possibly in both directions. If that's the case, here is what is happening.
The phone is registering using SCCP, which uses TCP. Call control also using TCP. The actual bear traffic, the voice, uses RTP which is a variant of UDP. UDP is not connection-oriented, like TCP, and because of these, many firwalls and NAT devices block it or just do not route it.
This would explain why the phone rings (that's the call control), but there is no audio and no errors; because UDP is connectionless, there is no error generated when a single packet, or every packet, gets lost en route.
So is there a NAT device on the ATA end? It is possible on some NAT/firewall devices to enable UDP traffic.
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 ...
This document describe how DST changes and how time changes are
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setting the clocks forward 1 hour from standard time during the summer
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