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Fax broadcasting means sending one fax to many recipients at once. An online fax service takes your document and a recipient list, then dials each number in turn, retrying busy lines. Because unsolicited fax advertising is illegal under federal law, legitimate services require proof of consent before they broadcast.
You upload the document once and provide the list of fax numbers, usually as a spreadsheet or CSV. The service then works through the list:
A dedicated fax machine can technically do this too, with a built-in broadcast or "group dial" feature, but it ties up the machine for hours on a large list. Online services run the list in the background, which is why almost all broadcasting is done through them now.
| Single fax | Fax broadcast | |
|---|---|---|
| Recipients | One | Dozens to thousands |
| Retrying busy lines | Manual | Automatic, over hours |
| Delivery reporting | One confirmation page | Per-recipient log |
| Legal risk | Low if solicited | High if any recipient did not consent |
This is general information, not legal advice.
In the US, the Telephone Consumer Protection Act bans unsolicited fax advertisements. You need the recipient's prior express invitation or permission before sending fax ads, and every fax ad must carry an opt-out notice with a working phone or fax number for removal requests. The law provides for statutory fines per offending fax, which means a careless broadcast to a bought list can turn into a serious liability very fast. Canada's rules are enforced by the CRTC, and unsolicited commercial faxes fall under the same anti-spam framework that covers email and texts.
Note the distinction: these rules target advertising and solicitation. Sending a requested form, a receipt, or documents to an existing customer relationship is a different situation. But if there is any doubt about whether the recipient agreed to receive it, treat it as a no-go.
Because the service provider shares the legal exposure. Many online fax services will not activate broadcast features until you confirm your list is opt-in, and some require explicit extra authorization once your recipient list crosses a threshold (often around fifty recipients). They may also require your account details on file so violations can be traced. This is not the service being difficult: it is the service protecting itself from junk-fax liability. If a fax provider offers broadcasting with no questions asked, treat that as a red flag, not a convenience.
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