PhoneView can still remotely control a phone(s) and take screenshots in SRST mode as long as the phone can still authenticate the command i.e. the Authentication URL is still reachable.
Therefore as long as the phone can still reach port 80 on the relevant UCM server configured in the Authentication URL remote control is still possible using the phones web server. When testing SRST this is typically achieved by using Access Lists to block just the SCCP/SIP signalling port (2000/5060) for the phone subnet, however another technique for SRST testing that does not require any network changes is:
- Create a Call Manager Group that has only one Call Manager node, typically the backup node (sometimes the publisher) i.e. CMG_SRST
- Create a new device pool for the SRST test site i.e. DP_SITE1_SRST
- In the SRST Device Pool (DP_SITE1_SRST) use all of the same settings as the normal device pool for the site except for the following:
- Set the Call Manager Group to CMG_SRST
Now set the device pool of the phone(s) you wish to perform SRST testing with to the DP_SITE1_SRST device pool, then reset the phones to download the updated settings. All phones using this Device Pool can now be set to SRST mode by stopping the Call Manager service on the backup node specified in the CMG_SRST Call Manager Group. Stopping this service should not affect normal operation for the other phones/sites, but will force the chosen phones in to SRST as the only UCM node they could register with is now offline. As only the Call Manager service has been stopped the authentication requests from the phones will work as normal, therefore PhoneView will also be able to control the phones as normal.
PhoneView uses CTI to control all phones by default, however is a phone is identified in PhoneView as 'Unregistered' it will automatically fallback to HTTP based control. Therefore it may be necessary to perform a group update (Group > Update > Cluster from the menu) to refresh the device registration status so PhoneView can choose the more relevant communications path to control each device.
The following diagram illustrates both CTI and HTTP control of an IP Phone: