CID Callback Number Validation explained

Offering a callback is great, but it only works if you dial the right number. The number a caller is calling from is not always the one they want back. They might be at a desk phone, behind a switchboard, or on a line that shows a blocked CID (caller ID). CID Callback Number Validation is the feature that catches those cases before your dialer wastes a call on a dead number.

The two checks it runs

When validation is on, VICIdial first checks the length of the caller's number. You set what counts as valid, for example 10 digits, or you can allow a range by entering something like 10-11 to accept both ten- and eleven-digit numbers. Anything outside that range is treated as bad straight away.

The second check is optional and uses a Filter phone group. You point validation at a group, and any number that matches it is treated as invalid. This is handy for blocking known bad ranges, withheld-number placeholders, or internal extensions that should never get a callback.

Reading the number back

If the number passes, VICIdial plays it back to the caller and asks them to confirm. A typical prompt sounds like: to get a call back on this number, press 1, or press 2 to use a different number. The system can speak the digits out loud, so the caller hears exactly what you captured.

If the caller presses to enter a different number, they type it on the keypad followed by the pound key, hear it read back, and confirm. If they fat-finger an invalid number twice, an error prompt plays and they go back into the queue rather than being stuck in a loop. There is also a faster ONLY_IF_INVALID mode that skips the read-back when the caller ID already looks valid, so good numbers sail through and only the suspect ones get the full confirmation dance.

Walk through the full flow once and the prompt set makes sense. There is a read-back prompt for the original number, a confirmed prompt for when they accept it, an enter-a-number prompt asking them to type one, a you-entered prompt that repeats what they typed, a confirm prompt asking them to accept or retry, an invalid prompt for a number that fails the checks, a re-enter prompt if they reject what they typed, and an error prompt for two bad tries in a row. It looks like a lot, but each one is a short line and the example scripts in the field descriptions give you a starting point to record from.

Where you set it up

This lives on the Ingroup right alongside the callback queue settings. You turn validation on, set the valid length, optionally choose the filter phone group, and record the handful of prompts: the read-back, the confirmation, the enter-a-number prompt, and the error message. Each prompt has an example script in the field description to copy from.

Validation only matters when you are offering callbacks in the first place. If you have not set that up yet, start with the in-queue callback walkthrough, then come back and add validation on top. The wider context for all of this is in the inbound call handling guide.

Why bother

A callback that goes to the wrong number is a wasted dial and an annoyed customer. Validation cuts down on both, and confirming the number out loud also gives the caller confidence that you have it right. If you want a managed box where this is ready to switch on, see our pricing page.