Security, privacy and 9-1-1 · For 3CTel customers
How do I block spam and robocalls?
Spam and robocalls are reduced in layers. Block specific numbers that call repeatedly, reject calls with no caller ID or send them to voicemail, and route unknown callers through the main menu so automated dialers drop off before a person answers. In Canada, STIR/SHAKEN is a framework that lets carriers verify that caller ID has not been spoofed, which helps identify suspicious calls. A 3CTel specialist can set these rules up with you.
Blocking and screening options
- Block list: add numbers that call repeatedly so they hear a busy tone or a rejection message. Administrators can manage the list in the admin portal under Call Routing → Blocked Numbers. A 3CTel specialist can make this change for you.
- Anonymous call handling: calls with withheld or invalid caller ID can be sent to voicemail or asked to record their name before the call rings through.
- Main menu first: most automated dialers hang up when they hear a menu. Routing unknown callers through the main menu while known customers ring straight to a person cuts nuisance calls without affecting real ones.
- Business-hours rules: after-hours robocalls go to voicemail or the AI receptionist rather than waking anyone's cell phone.
What STIR/SHAKEN does and does not do
STIR/SHAKEN is a caller ID authentication framework that Canadian carriers apply to calls on IP networks. When a call is placed, the originating carrier attaches a signature attesting to how confident it is that the caller is entitled to use that number. The receiving carrier checks the signature and can pass a verification indicator to the phone.
It helps identify calls whose caller ID is verified, and it makes large-scale spoofing harder. It does not block calls by itself, and calls from networks that do not sign traffic may show as unverified even when they are legitimate. Treat it as one signal, alongside your own rules.
Keeping real customers unaffected
Aggressive blocking can catch legitimate callers, for example a customer calling from a hospital or a government office where the outbound number is withheld. Review the block list and anonymous-call rule after a few weeks, and check voicemail from screened calls so a real enquiry is not missed. If a specific number needs to bypass screening, it can be added to an allow list.
3CTel does not control whether other carriers sign their calls or how they display verification. Rules on your account affect how calls are handled once they reach your system.
Related questions.
Can I block calls from a whole area code or country?
Yes. Pattern-based rules can block or screen calls by prefix, which is useful for businesses that never receive legitimate calls from certain regions. Apply them carefully so you do not block customers who travel.
Will call blocking work on the mobile app?
Blocking is applied on the system before a call rings any device, so a blocked number never reaches the desk phone, desktop app or mobile app. Your personal cell number's own blocking is separate.
Do robocalls still cost me anything?
Incoming calls to a local number generally do not carry a per-call charge, but toll-free numbers can. Screening unknown callers on a toll-free line is worth setting up for that reason.
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