I know I am late to the party but I have looked at this on occassion. It is sometimes difficult to nail this down but since you are using EM heavily/exclusively, there are more options available to you than for most.
In general, the approach to leverage CDRs. The assumption is that if someone is sitting near a phone they may be using it. Even with EM, if they are logging into a phone they are likely using it. If the phone is being used and CDRs are being logged (and also assuming the record retention time is adequate) then you have the data needed to answer the question.
Where EM gives you a slight advantage is that people are logging in and I believe this is being tracked in the extensionmobilitydynamic table. Running the following query on your UCM cluster may give you some useful information:
select eu.userid, emd.logintime, emd.loginduration, emd.datetimestamp
from extensionmobilitydynamic emd inner join enduser eu on emd.fkenduser_lastlogin=eu.pkid
order by eu.userid
The above will dump out a list of end users and the emd.datetimestamp field is a value (stored as epoch time) of when that user logged into the device. The output will be a history of sorts. I do not know if the data is purged periodically or not. I haven't explored this close enough yet. Also, you may need to adjust the query to see current logged on users:
select eu.userid, emd.logintime, emd.loginduration, emd.datetimestamp
from extensionmobilitydynamic emd inner join enduser eu on emd.fkenduser=eu.pkid
order by eu.userid
The above is close (I assume) to what the reporting tool that Yosh mentioned is doing.
You can run these queries from the CLI on one of the UCM nodes. You can also leverage the query tool that Cisco provides. You can also build or acquire a tool that allows you to submit queries and dump reports. I do that latter with a homegrown app. A series I wrote on using the Cisco provided query tool (be prepared to parse XML) is here:
http://www.netcraftsmen.net/resources/blogs/running-sql-queries-on-cucm-6x7x-using-axl-soap-toolkit-part-1.html
HTH.
Regards,
Bill
http://ucguerrilla.com
