An overflow call is a call that cannot currently be taken by any agents or answered by voicemail. This can happen for the following reasons:
- All agents are offline.
- All agents decline an incoming call.
- All agents miss an incoming call.
- The maximum queue wait time is exceeded.
- The maximum queue size is reached.
When voicemail in Talk is turned off, and when no agents are available to take a call, Talk defaults to your configured voicemail-off greeting, and then disconnects the call.
Adding an overflow number to a Talk number
To provide for a better experience for callers, you can add an overflow phone number to each phone number you added to Talk (not including external numbers).
When a call is not answered by an agent, and voicemail is off, the calls will be sent to the overflow number. This might be the number of an external support organization, or an on-call agent that you use outside of your normal business-hours, or during holidays.
Things to consider when you set up an overflow number include:
- When Talk sends a call to an overflow number that is not a Talk number, a Support ticket is created. This ticket contains the tag, call_overflow.
- When a call is sent to an overflow number that is a Talk number, a regular ticket with no tag is created.
- If recording is enabled for that number, any tickets created include a recording of the overflow call.
- Overflow calls are charged as normal calls, including recordings, when enabled.
If you want Talk to always send calls to the overflow number when they cannot be answered, see Adding an overflow number.
If you want Talk to send calls to the overflow number depending on the business-hours you have configured, see Adding an overflow number when business-hours are configured.
Adding an overflow number
Use this procedure to check your call routing settings, and then configure an overflow number.
To add an overflow number
- Make sure that the Schedule setting on the Routing tab is set to Always route calls.
- Click the Admin icon (
) in the sidebar, then select Channels > Talk.
- Select the Numbers tab.
- Click the number you want to edit.
- On the Overflow tab of the phone number settings, turn on Overflow calls.
- Enter a valid phone number that calls will be overflowed to.
- When you are finished, click Save changes.
Now, when calls are not answered by an agent, and voicemail is off, calls will be diverted to the overflow number you entered.

Adding an overflow number when business-hours are configured
The procedure to add an overflow number when business hours are configured is different to the standard overflow number.
To add an overflow number when business-hours are configured
- Make sure that the Schedule setting on the Routing tab is set to Business Hours.
- Click the Admin icon (
) in the sidebar, then select Channels > Talk.
- Select the Numbers tab.
- Click the number you want to edit.
- On the Overflow tab of the phone number settings, you can turn on Overflow calls for calls the number receives during the schedule you configured on the Routing tab. Additionally, you can also turn on Overflow calls for calls the number receives outside of the schedule you configured.
- For each item you configured, enter a valid phone number that calls will be overflowed to.
- When you are finished, click Save changes.

Now, when calls are not answered by an agent, and voicemail is off, calls will be diverted to the overflow numbers you entered, according to the schedule options you configured.
17 Comments
I'm on Enterprise and have Talk but don't appear to have these options available. What do?
Hi Colin, sorry you are not seeing these options. I've contacted the Talk team, and feel that the best thing to do is to open a ticket, so that your problem can be investigated properly. Hopefully, someone will contact you soon.
I really do appreciate having this ability added to Zendesk Talk, since this capability is an integral part of every other phone system, but I now have to choose between two vital services and cannot have both voicemail and after-hours routing.
Our customers love being able to leave a voicemail instead of waiting in the queue, and others love being able to use the callback feature, and we would love to be able to cancel our 3rd party IVR that we've been forced to maintain ever since beginning to use Zendesk Talk, but forcing us to turn off the voicemail feature in order to be able to route calls after-hours or utilize overflow routing makes the service completely unusable for us.
I love the fact that this new feature brings Zendesk Talk that much closer to parity with other support phone systems, but we would love to be able to use this new feature without having to shut down a critical feature our customers use every day.
Hi Bob, thanks so much for leaving this feedback. I'll make sure it's passed on right away.
Hey Bob,
I'd consider having the ability to choose between voicemail and overflow routing (not just having either or) to be a second iteration of this feature functionality, which is something we definitely want to do. Good to know we're thinking along the same paths!
Thanks for reaching out. Caroline
Is there the option of an customisable automated message in the event of a service disruption? I.E - can we record a message and have it play prior to the call delivery?
Hello Zak,
Currently there is no system in place to offer a message before it reaches our call routing. We do have options for enabling failover numbers that we outline in the following article.
https://support.zendesk.com/hc/en-us/articles/203906366-Managing-Zendesk-Talk-numbers#topic_fkr_j2d_yt
Do I have to have a second group of agents for this to work? What if I used one of our other numbers as the overflow number but it was still routed to the same group of agents? Essentially, this would just increase their wait time and our max queue size. Is that correct?
I have a small team and we sometimes max out but our customers would prefer a longer wait time than being disconnected.
Hey Emily,
You won't need to set up a second group on your account for this functionality to work. You'll just want to make sure your voicemail is disabled to use this feature. Once the call is sent to the other Talk number then that numbers max queue and wait time rules should set in.
Hope this answers your questions :)
Awesome! Thank you!
Happy to help :)
Is a use case for this when Zendesk Talk is down? Can calls to Talk numbers be routed to a non Talk number? My team is interested in developing a fail safe workflow. Thanks!
I am using Overflow into a Talk Number. Is there a way I can report on the number of calls that are hitting the Overflow? Any help would be greatly appreciated as I want to see how many calls we are missing.
Is there a way to configure this overflow so that it jumps from 1 group of agent to another group instead of an external number ?
Any hints on a way to achieve that ?
Hi Jean,
You could technically have another Zendesk Talk number as your overflow number that you've set up. You would then set up Group routing for that second Talk number you're using.
I hope that points you in the right direction!
Can you have the voicemail disabled within business hours only.
So for example use overflow during office hours. Still have calls to voicemail outside of office hours?
Hey Emma,
As long as you enable scheduled routing under the Routing tab of your Talk number, you should see an option to disable Voicemail within business hows and enable outside of business hours. Screenshot for you below:
More information in the following article: Configuring voicemail options
Let us know if you have any other questions!
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