This document describes defined call states that Cisco CallManager
sends to Skinny Client Control Protocol (SCCP) endpoints such as Cisco
7960/7940 IP phones. However, these call states are not used by Cisco
Cisco recommends that you have knowledge of Cisco CallManager.
The information in this document is based on all versions of Cisco
The information in this document was created from the devices in a
specific lab environment. All of the devices used in this document started with
a cleared (default) configuration. If your network is live, make sure that you
understand the potential impact of any command.
Technical Tips Conventions for more information on document
The SCCP protocol is a Cisco protocol standard for real-time calls and
conferencing over IP.
An H.323 proxy can be used to communicate with the Skinny client using
the SCCP protocol. In such a case, the telephone is a Skinny client over IP, in
the context of H.323. A proxy is used for the H.225 and H.245 signaling.
With the SCCP protocol architecture, the majority of the H.323
processing power resides in an H.323 proxy — the Cisco CallManager. The end
stations (IP phones) run the Skinny client, which consumes less processing
overhead. The client communicates with CallManager using connection-oriented
(TCP/IP-based) communication to establish a call with another H.323-compliant
end station. Once Cisco CallManager has established the call, the two H.323 end
stations use connectionless (UDP/IP-based) communication for audio
This list defines the call states that are sent to SCCP endpoints, such
as Cisco IP phones by Cisco CallManager in SCCP protocol. Cisco CallManager
functions as an H.323 proxy. These are not the call states used in Cisco
CallManager internally. Instead, they are the call states sent from Cisco
CallManager and understood by the SCCP endpoints:
7—Line In Use
13—In Use Remotely
This Cisco CallManager trace shows that Cisco CallManager sent 2 (see
boldface characters) to the SCCP endpoint. It represents the call state of
03/01/2006 16:43:19.808 CCM|StationD:
(0000044) CallState callState=2 lineInstance=1