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SIP SRST on 6921 SCCP configured phones

Level 1
Level 1

Hi all,

I'm working on a CUCM 8 installation with mainly 6921 IP phones. We are using SCCP protocol in this installation but unfortunately these phones do not support SCCP SRST on any version of software.

Is it possible to configure a SIP SRST and to use in on these phones which normally communicate with the CUCM with SCCP protocol?

The idea is to upload the SIP firmwares and publish them on the SRST router so the phones do a software upgrade everytime they fallback to the router and vice-versa, when the CUCM is back online, to SCCP firmware.

Is there any chance that this scenario will work?

2 Replies 2

paolo bevilacqua
Hall of Fame
Hall of Fame

What do you mean they don't support SCCP SRST.

With SRST in CME mode, you will have same or better features than CM.

And CME supports the 6921, so there is no issue.


As you can see even in the data sheet for the newest version of SRST 8.5 :

"Cisco Unified SRST is not dependent on Cisco Unified Communications Manager versions but on IP phone loads."

So based on this I think that my question does make sense!