Auxiliary (AUX) Codes
Auxiliary codes — also called AUX codes or reason codes — are the codes a contact centre agent selects to record why they're logged in but not taking calls.
Tea break, lunch, training, admin, a coaching session: each is captured against an auxiliary code, so the centre can see where agent time goes when it isn't spent on the phone.
They're a workhorse of contact centre reporting and workforce management — they feed shrinkage, scheduling and adherence. But they come with one big blind spot that's easy to forget.
This guide explains what auxiliary codes are, how they work, the common ones, the trap of reading too much into them, and how to set up a sensible, respectful set.
What it is
A reason code an agent selects when they go "not ready", recording why they're unavailable for calls — break, training, admin and so on.
Why it matters
Auxiliary time feeds shrinkage, scheduling and adherence — so the codes shape how accurately you can plan and resource the centre.
What this guide covers
What AUX codes are, how they work, the common ones, the output they can't measure, best practice, and how they differ from wrap codes.
What are Auxiliary Codes?
In plain English
When an agent is logged in but not available for calls, they're in an "auxiliary" (unavailable) state — and the auxiliary code records the reason. It's how the system answers the question: "they're logged on, so why aren't they taking calls right now?"
The term comes from the contact centre's ACD (Automatic Call Distributor), which routes calls to available agents. To stop calls being delivered for a legitimate reason — a break, a meeting, some admin — the agent goes "not ready" and picks an auxiliary code to say why.
What they are
Reason codes for agent time spent not taking calls while logged in — the categories of "unavailable" time, used for reporting, scheduling and shrinkage.
What they aren't
They are not a record of why the customer called (that's wrap or line-of-business codes), and they are not a measure of how productive the agent was in that state.
How Auxiliary Codes Work
Auxiliary codes are a feature of the ACD or contact centre platform. The flow is simple and happens dozens of times a day.
Agent logs in
Once logged into the ACD, the agent is available and calls are routed to them according to the routing strategy.
Agent goes "not ready"
To stop calls being delivered — for a break, admin or a meeting — the agent presses the "not ready" or "unavailable" button.
They pick a reason
The system prompts for an auxiliary code — lunch, training, emails — so the unavailable time is tagged with a reason.
It's reported
Time in each code rolls up into real-time dashboards and interval reports, feeding shrinkage, scheduling and adherence.
Some states are triggered automatically — for example, After-Call Work can kick in for a set time after each call so the agent can finish wrapping up before the next one is delivered.
Common Auxiliary Codes
The exact set is yours to configure, but most centres draw from a familiar list. They tend to fall into a few groups.
Breaks & personal
Tea or rest break, lunch, and a general "Personal" code for short, human reasons — grabbing a drink, the bathroom, a quick stretch.
Work that isn't inbound calls
After-call work, outbound calls, emails and written correspondence, back-office or admin tasks — productive time, just not on inbound calls.
Development & people
Training and e-learning, coaching sessions, one-on-ones and team meetings — time away from the queue to build skills or align the team.
Operational
Escalations, system or outage issues, and project work. These vary most between centres and are where "code sprawl" usually creeps in.
The Blind Spot: Time, Not Output
Here's the thing most easily forgotten about auxiliary codes: they tell you where time went, not what came of it.
An example
Say an agent spent three hours in an "Emails" auxiliary code. You know they were on emails for three hours — but you have no idea whether they answered three emails or thirty.
The code captures the time and the category; it says nothing about the productivity or output of that time.
⚠️ Don't treat AUX time as a productivity measure
Because the codes look precise, it's tempting to manage agents on their auxiliary time alone — "you've had too long in admin this week".
But without an output measure alongside it, AUX time is only half the picture. Two agents with identical "Emails" time may have wildly different results. Use auxiliary codes to understand how time is distributed and to plan resourcing — not as a standalone verdict on whether someone is working hard.
Setting Up Auxiliary Codes Well
A good set of codes gives you useful insight without drowning agents in admin or treating them like suspects. A few principles help.
Keep the list lean
It's tempting to account for every second, but more codes means more mis-codes and more friction. Many centres keep to around five well-chosen codes — enough to plan with, few enough to use accurately.
Be clear on log-out vs AUX
Decide when to use an auxiliary code versus logging out entirely. A common rule: stay logged in (in an AUX state) for paid activity, and log out for unpaid breaks such as lunch.
💡 Use "Personal", not "Toilet"
Having a dedicated bathroom code is demeaning, and it signals a culture of surveillance rather than trust. A single "Personal" code covers the bathroom, a drink, a stretch or a moment to reset — with dignity.
How you treat the small things shapes the employee experience, and that shows up in attrition and service quality.
💡 Review the codes regularly
Codes accumulate over time and quietly lose meaning. Review them periodically: retire ones nobody uses, merge overlapping ones, and make sure each still earns its place in your shrinkage and scheduling picture.
AUX Codes vs Not Ready vs Wrap Codes
A few closely related terms get tangled together. Here's how they line up.
AUX codes & "Not Ready" codes
These are essentially the same idea under different vendor labels. "Not ready" is the agent state; the auxiliary (or reason) code is the why attached to it. Many platforms and people use the terms interchangeably — see our Not Ready Codes guide for the same concept from the state angle.
Wrap / Line-of-Business codes
These are a different animal. Wrap codes (also called line-of-business or disposition codes) capture why the customer called — sales, complaint, billing — not why the agent is unavailable. AUX codes are about the agent's time; wrap codes are about the contact's reason.
The one-line distinction
Auxiliary / not-ready codes answer "why isn't this agent taking calls right now?" Wrap / line-of-business codes answer "what was that contact about?" Both are reason codes, but they describe completely different things — and mixing them up will scramble your reporting.
Frequently Asked Questions About Auxiliary Codes
What are auxiliary codes in a call centre?
Auxiliary codes (also called AUX codes or reason codes) are the codes an agent selects to record why they're logged into the ACD but not taking calls — for example lunch, training, admin or a coaching session. They tag the agent's "unavailable" time with a reason, so the centre can see where time goes and feed it into shrinkage, scheduling and adherence.
What's the difference between aux codes and not ready codes?
They're essentially the same concept under different labels. "Not ready" is the agent state — logged in but not accepting calls — and the auxiliary or reason code is the why attached to that state. Different ACD vendors use different terms, and many people use them interchangeably. The underlying idea is identical: recording why an agent isn't taking calls.
What are some common auxiliary codes?
Common ones include after-call work, outbound calls, tea or rest breaks, lunch, training and e-learning, emails or written correspondence, coaching, meetings, escalations and a general "Personal" code. The exact set is configured in your ACD, and most centres keep it deliberately short — around five well-chosen codes.
Are auxiliary codes the same as wrap codes?
No. Auxiliary codes record why an agent is unavailable for calls. Wrap codes — also called line-of-business or disposition codes — record why the customer called, such as sales, billing or a complaint. They're both reason codes, but they describe completely different things: one is about the agent's time, the other about the contact's purpose.
Do auxiliary codes measure productivity?
No, and this is the key limitation. Auxiliary codes tell you where time went — three hours in "Emails", say — but nothing about the output of that time, like how many emails were actually handled. Treat AUX time as a view of how time is distributed for planning and shrinkage, not as a standalone measure of how hard someone is working.
How many auxiliary codes should a call centre use?
Fewer than you might think. It's tempting to account for every second with a long list, but more codes means more mis-coding and more friction for agents. Many centres settle on around five well-chosen codes — enough to plan and report with, few enough to be used accurately and consistently.
Should there be a dedicated "toilet" auxiliary code?
No — it's demeaning and signals surveillance over trust. Use a single "Personal" code that covers the bathroom, getting a drink, a stretch or a quick reset. How you handle the small things shapes the employee experience, which feeds directly into attrition and service quality.
Where to Next
Summary: Auxiliary Codes
Auxiliary codes — AUX codes or reason codes — are how a contact centre records why an agent is logged in but not taking calls, from lunch and training to admin and coaching.
They're set in the ACD, reported in real time and at interval, and they feed shrinkage, scheduling and adherence.
Their great limitation is that they measure time, not output: knowing an agent spent three hours in "Emails" tells you nothing about how many emails they handled. Use them to understand how time is distributed and to plan resourcing — never as a standalone verdict on productivity.
Set up a lean, respectful set (a "Personal" code, not a "Toilet" one), be clear about when to log out versus go AUX, and review the codes regularly. And don't confuse them with not-ready codes (the same idea, the state angle) or wrap / line-of-business codes (why the customer called).
