Aux is not used in just one way. I believe the best practice is to use Aux for non-contact related time tracking only, and to look at adherence to some degree. Some people will use Aux (or equivalent) with codes that indicate where the call center agent's time is spent -- breaks, lunch, training, special projects, etc. That can provide more insight into where time is spent if the automatic call distributor (ACD) offers such codes.
A typical challenge with Aux and scheduling is that call center agents may abuse it if they have target metrics in other areas, such as wrap-up time, but don't have a target in this area or in adherence or some other measure of where they spend their time. In some companies, policies require that logging out occur once per day, at the end of the shift, to enable tracking through the system, with Aux or related workstates tracking unavailable time. Other call centers will have agents log out for breaks and lunch, or other non-call related activities. Consider tradeoffs based on the system capabilities and how the system (ACD and workforce management (WFM)) track the time and call center schedule, especially in multi-skill environments.
This was first published in September 2007