In SRST third party sip phones I think are not supported. However, you can configure Fall back to CAll Manager Express and get you SIP Phone support. I think support for SIP Phones was available with CME 4.2 and above. So if the phone can support multiple connections from top down, you can set the CME as the third server to connect to when the first two or first one is not available.
Someone else may have a better idea, but this is just my humble opinion.
SIP SRST Admininstration Guide states the following:
Cisco Unified SIP SRST can support SIP phones with standard RFC 3261 feature support locally and across SIP WAN networks.
So I think that it is possible but theoretically. If the phone support dual registration with CCM and any backup registar server then it works. And it doesn't matter whether this registrar is CME or SRST.
CME and SRST is pretting much the same thing. If you're running the later version of SRST 4.2, then yes it is supported since it is support in CME. I was wrong on the first part of my posting. Thanks on the update privateer.
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
months, and back again in the fall, in order to make b...