For login, you could use the login URL. There is also a logout URL you can use.
Is this what you are looking for?
The APIs which support Extension Mobility are:
- Extension Mobility API: a small HTML/XML API allowing login/logout/logout-all/device-user query. Requires end-user credentials or a designated E/M 'proxy' user credentials:
- AXL: an extensive SOAP API for configuring/managing all of CUCM. Required CUCM admin-level credentials:
However, neither support cross cluster extension mobility scenarios - only single-cluster.
I have heard of developers examining the HTTP requests/responses of a phone performing EMCC function via the on-screen display and essentially reverse-engineering the HTTP messaging, so its something to consider. However note this is not an officially supported 'developer interface', which may have support implications if the mechanism changes at some point in the future.