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Support for Shared line in SRST 7.1

JK Kumar

I have a SRST gateway (mode SRST) running IOS code 15.0(1)M3 which corresponds to SRST 7.1. When the gateway falls into SRST mode, I noticed that when I call the shared line i.e. 2300, only 1 of the 4 phones (which has shared line) rings.

The shared line behaves correctly in normal mode (when phones are registered to CUCM).

in SRST mode, all the phones register to SRST gateway.


I am wondering if Shared lines are supported when using 9971 and 7965  phones (SIP) in SRST 7.1 ?   The SRST roadmap document is ambiguous.

Thank you.


5 Replies 5

Aman Soi



You can refer the link for shared lines which says Shared line is supported with SIP in E-SRST mode.


Also, there are tables 9,10 and 11 which says what all features are supported ..



Aman, i had looked @ those tables. However, its not clear WHICH version of SRST

 supports Shared lines on which kinds of phones.

I hope the documentation can be fixed to show this



In your SRST configuration do you have your "max-dn" command including either dual or octo lines?  If you configure "max-dn XX dual" you should be able to receive 2 calls on the shared line.  If you configure "max-dn XX octo" you should be able to receive 8.  XX = number of DNs allowed to register in SRST.


Hi jbouwkamp,  Thank you!

I dont see an option to add "dual" or octo under voice register global.

i.e. I have max-dn 100,

but no option to do max-dn 100 dual

Does this mean I dont have ESRST ? I have a standard UC license.


Nathan Compton

Are you sure all phones are setup as SIP? Shared lines don't work the same if you are sharing a line between sccp and sip phones in SRST mode.  I don't think they work at all between the 2 on version 7.1 SRST.

If both phones are sip, do a "show voice register pool" while in SRST mode. Check to see if the same voice register dn is assigned to the phones. There is a small chance the voice gateway is creating multiple voice register dns for the same extension number.


E-SRST is an application installed on a SRE module to enhance SRST functionality. I wouldn't get too hung up on it.

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