Combined, wherever the till layout and budget allow - it removes the separate action that gets skipped once a queue forms.

A combined unit deactivates during the same movement that scans the barcode, so compliance is automatic.

A standalone pad requires a deliberate second pass, and under queue pressure that is the first step to disappear.

Standalone pads are cheaper and can be retrofitted to any counter, which is why they remain common.

Where a pad is used, position it so items pass over it naturally on the way to bagging rather than off to the side.

Under-counter pads deactivate through the counter surface and keep the workspace clear, but the effective range through the material has to be checked.

A limited distance - enough for ordinary packaged goods, and often not enough for a label deep inside a large box.

The field falls off quickly with distance, so the label has to pass reasonably close to the pad.

Large or deep items are the recurring problem: the label is inside the packaging and never gets near enough.

Identify those products during setup, and give them a defined handling step - passing the correct face across the pad, for instance - rather than discovering the issue at the door.

Counter material matters for under-counter units. A thick stone or metal-reinforced counter reduces the effective range substantially.

Test the range with the actual products and the actual counter rather than accepting the specification figure.

By a confirmation at the pad - tone, light or a signal to the point of sale - and by verification at the pedestal.

Without feedback, nobody knows which labels were missed until they alarm at the door.

The confirmation tone must be distinguishable from the scanner's own beep, or operators will not hear the difference.

Reporting to the point of sale is the strongest option, because a transaction containing an un-deactivated item can be flagged before the customer walks away.

Pedestal-side deactivation verification catches what the counter missed and classifies the alarm as a process failure rather than a theft.

Review the data weekly by till. The pattern usually points at one counter layout or one shift rather than at a general problem.

Yes. Radio-frequency labels are permanently detuned; acoustomagnetic labels are demagnetised, which is in principle reversible.

The radio-frequency deactivator applies enough energy to break down a deliberate weak point in the label's circuit, so the change is irreversible.

The acoustomagnetic deactivator removes the magnetic bias the label needs to resonate at the detection frequency.

A strong magnet can in principle restore that bias, which is not a common attack but is a reason to verify rather than assume.

The two are not interchangeable: an acoustomagnetic deactivator does nothing to a radio-frequency label.

A store running both technologies needs both at every till, and operators have to know which product uses which.

Weekly testing with a live label - it fails silently, and the first symptom is a rise in door alarms.

A dead pad looks exactly like a working one. Only a deliberate test distinguishes them.

The test takes seconds: pass a live label over the pad, then check it no longer responds with a handheld detector or at the pedestal.

Log the result. The record is what distinguishes a hardware failure from a training problem when alarms increase.

Physical damage is common at a till - spillage, impact and cables pulled - so a visual check belongs in the same routine.

Interference from other equipment at the counter can reduce effectiveness, so retest after any change to the till layout.

It can affect magnetic media and some electronic items, so products sensitive to magnetic fields need checking.

Acoustomagnetic deactivators in particular produce a strong field at close range.

Magnetic-stripe cards, older magnetic media and a small number of sensitive electronic devices can be affected if passed directly across the pad.

Most modern packaged goods are unaffected, but the question is worth asking for specialist stock.

Manufacturers publish guidance on sensitive product types and minimum distances.

Where a store sells such items, a handling instruction at the till is simpler than changing the technology.

One per till at minimum, plus any point where goods leave without passing a till - collection desks, customer service and self-checkout.

Sharing a deactivator between tills creates a bottleneck and guarantees skipped labels.

Self-checkout is the position most often missed, and it is exactly where a missed label causes the most customer embarrassment.

Click-and-collect and customer service desks hand over goods that were never scanned at a normal till and need their own provision.

Returns desks need one too, both to check incoming items and because returned stock is relabelled.

Count the paths out of the store rather than the tills. Any route that produces a customer with goods and no deactivation is a source of door alarms.