Repeated nuisance calls
A number keeps calling the switchboard several times a day just to cause trouble. You add it with a note on why: from then on it gets busy and your operators are no longer interrupted.
Phone system
Block calls from numbers you never want to hear from again
Add a number to the blacklist and its inbound calls get busy before they reach menus, queues or operators. You can block callers with hidden numbers too.
Blacklist
+44 7700 900 418Nuisance calls · 14 blocked
Anonymous numbersWithheld number · 38 blocked
+44 20 7946 0321Telemarketing · 6 blocked
What it is for
The blacklist is the list of numbers you do not want calls from. It applies to every phone number of your cloud phone system: an inbound call from a blocked number gets busy and ends.
The block happens before anything else: the call is not answered, does not go through the IVR menu, does not join a queue and rings no operator. Since it is never answered, it is not billed.
With the "Anonymous numbers" switch you block, in one go, every call that arrives without a number, such as private or withheld numbers.
For each blocked number you see how many calls were refused and when the last attempt was, and in the call report the call shows with the Blacklist outcome.
Use cases
Withheld numbers clogging the queue
A support line gets many hidden-number calls that tie up operators without a real request. You turn on "Anonymous numbers", and anyone who wants to talk to you has to show their number.
Sales calls from other call centres
The same telemarketing number calls a company's switchboard every week. You block it and write "telemarketing" in the Note so everyone knows why it is there.
Checking whether a block is still needed
After a few months you look at "Blocked calls" and "Last blocked": a number that stopped calling long ago comes off the list, one that keeps trying stays.
Test lines or automated systems
A supplier's automated system dials your public number by mistake. You block it until the issue is fixed, then delete the entry and it can call again.
How it works
Open the blacklist
In Phone modules open Blacklist and click "Add number".
Enter the full number or choose anonymous
Type the number in international format with its country code: only that exact number is blocked. Or turn on "Anonymous numbers" to block calls without a number.
Add a note
Use the Note field to say why the number is blocked, so whoever manages the phone system understands it months later.
The call is refused
When that number calls one of your phone numbers, the phone system recognises it at once and returns busy. The call detail shows the step "Blocked: the number is blacklisted".
Review and unblock any time
The list shows how many calls each number had refused and when it was last blocked. Delete the entry and the number can call again.
What you can set
Number to block
- Number
- The full number in international format: only calls from this exact number are blocked, not similar ones.
- Anonymous numbers
- Instead of a number, blocks every call that arrives without a caller number.
- Note
- Free text of up to 255 characters to remember why the number is blocked.
List and statistics
- Blocked calls
- How many inbound calls from that number have been refused so far.
- Last blocked
- Date and time of the last call refused from that number.
- Summary
- At the top of the page you see how many numbers are blacklisted and the total of blocked calls.
- Edit and delete
- Change the number or the note any time; deleting an entry lets that number call again.
How the call is handled
- Busy
- The blocked caller hears busy: the call is not answered and never reaches menus, queues or operators.
- No charge
- A call refused by the blacklist is never answered, so it is not billed.
- Call report
- The call stays in the report with the Blacklist outcome, which you can filter by as end reason.
Frequently asked questions
How do I block a number on my phone system?
Open Blacklist in Phone modules, click "Add number", type the full number with its international code and save. From then on its calls get busy.
Can I block calls from withheld or private numbers?
Yes. In the add dialog turn on "Anonymous numbers": every call that arrives without a number is refused.
What does a blacklisted caller hear?
A busy tone. The call is not answered, so they hear no message and never reach an operator.
Does the blacklist stop us from calling that number?
No. The blacklist applies to inbound calls; your operators can still call that number.
Can I block a whole prefix or a range of numbers?
No. Each entry blocks one exact number. To block several numbers, add an entry for each.
Do blocked calls cost anything?
No. The phone system refuses them without answering, so they are not billed.
Related features
Try it on your own phone lines
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