It is not mentioned in the compatibility matrix (CSR Compatibility Matrix) and in the device -pack list it is there but apparently as an SCCP phone ( Cisco Unified Communications Manager Device Package Compatibility Matrix - Current Cisco Unified Com...

Hello,I remember from a conversations I had many moons ago that ISR 4K were not supporting SRST fall-back to SIP trunk (CUBE). Is it still the case? In certain countries ISDN connections are not provided by SP's and we would have the need to provide ...