A dialler retrying a dead number walks it across every gateway in the group: same number, same second, one attempt per gateway. On your side that means several identical CDRs, several hits on your carriers, and capacity spent on a handset that is switched off, doesn't exist, or simply isn't answering.
The Repeat Dial Guard breaks that pattern: when a customer dials a number, that number is held for them for as many seconds as you choose. If they dial it again inside that window, NEXIA answers 503 instantly — before rating, routing, or touching a single carrier — and their dialler moves on elsewhere.
Turning it on
It is a per-customer setting, under Users → (edit customer) → Repeat Dial Guard. It only appears for customers that have origination points: it acts on the calls a customer sends you, so it makes no sense on a termination carrier.
- Reject a number this customer just dialled — turns the guard on.
- Window (seconds) — how long each dialled number is held (30 by default). With the guard off the field is disabled, and the value is kept for when you turn it back on.
What it does, exactly
| Situation | What happens |
|---|---|
| Customer dials the number for the first time | Goes through normally. The number is held for that customer for the length of the window. |
| They dial it again inside the window | Immediate 503. Not rated, not routed, not offered to any gateway, and no CDR is written. |
| The call was answered | Its hold is released at once: a number that connected is not what the guard is for, so you can ring it back immediately. |
| A different customer dials the same number | No effect. The hold is per customer; the number stays dialable by everyone else. |
| The window elapses | The number is free again, with no intervention. |
Why 503 and not another code
Because it is re-routable: the customer's dialler reads it as "try another carrier" and keeps working, instead of writing the number off. It is the same policy as every other internal rejection — see Hangup Causes.
Why no CDR is written
The first attempt is already recorded with its real outcome. The suppressed retries add no information: counting them would only multiply that one row and clutter your reports. They are counted in the switch log instead, which is where they matter when you are tuning the window.
Choosing the window
It depends on the customer's dialler behaviour, not on your network:
- 15–30 s — kills the immediate burst (the typical case: the same number repeated in the same second, once per gateway) without disturbing the normal pace of a campaign.
- 60 s or more — for customers whose dialler keeps hammering the same number for minutes.