Calling window

The federal baseline in the US restricts telemarketing to between 8am and 9pm in the called party’s local time. Several states impose narrower windows, some restrict weekends, and other jurisdictions have their own rules entirely. Many organisations therefore run a conservative window inside the legal minimum, on the basis that calling at the edge of what is permitted is both risky and unproductive.

Determining recipient-local time is the hard part. An explicit timezone on the contact record is authoritative when it exists. When it does not, the area code of a North American number is the usual proxy — but several area codes straddle a timezone boundary, and the failure is asymmetric: assuming Eastern for a number that is actually Central shifts the whole window an hour later and can push a call past the cutoff.

A robust implementation does not merely block out-of-window calls; it reschedules them. Blocking silently drops contacts from a campaign, whereas computing the next moment the window opens and requeuing preserves the attempt. Weekend and holiday suppression has the same requirement — the contact must land at the next permitted opening rather than disappearing.