DTMF Masking vs Pause & Resume: Technical Comparison

How each one actually works

Both promise to keep card numbers out of your call recordings, but they do completely different things under the hood. DTMF masking sits in the call path: the customer keys their card number on their phone keypad during a live call, and the keypad tones are flattened to a single flat tone before they reach the agent, the recording, or any application. The real digits go straight to the payment gateway. Nobody pauses anything — the agent stays on the line the whole time and the recording runs clean.

Pause-and-resume works the other way round. The agent asks the customer to read their card number out loud and types it into a payment screen, and a trigger tells the call recorder to stop writing to disk for those few seconds, then start again. The card data is still spoken aloud, still heard by the agent, still sitting on the agent's PC — it just isn't in that one recording file.

What happens to your PCI scope

This is where the two part company, and it's the part that costs you money. With DTMF masking done properly, the agent never hears or sees the digits and the recorder never captures them, so the agent's desktop, headset, and the recording server all drop out of your cardholder data environment. Most contact centres move from SAQ D to SAQ A as a result — a shorter, cheaper audit every year.

Pause-and-resume doesn't do that. The card number is live in the room: the agent hears it, types it, and it passes through their PC and headset. Pausing the recorder protects one file; it doesn't take any of that equipment out of scope. Most QSAs now treat pause-and-resume as a controls-only mitigation, not a descoping measure, so you stay on SAQ D and keep paying for the bigger assessment.

The agent and customer experience

DTMF masking is the quieter option day to day. The agent talks the customer through keying their card, stays on the line in case anything goes wrong, and average handle time barely moves. The customer never has to switch channels or wait on hold.

Pause-and-resume leans on the agent to do the right thing every time — trigger the pause, take the number accurately, resume — and it only takes one missed trigger or one mistyped digit for card data to land somewhere it shouldn't. It also means your agents are still hearing card numbers all day, which some customers, and some compliance teams, aren't comfortable with.

So which should you choose?

If your goal is to genuinely shrink your PCI scope and your audit cost, DTMF masking wins — it removes the agent and the recording from the equation rather than papering over one recording. Pause-and-resume can have a place as a stop-gap on a legacy system you can't change yet, but don't let a vendor sell it to you as descoping, because it isn't.

We built Paytia around masking for exactly these reasons. Our DTMF masking flattens the tones at the carrier, before they reach the agent or the recording, so the agent stays on the line and the endpoint never enters scope — and we don't sell pause-and-resume, because we don't think it descopes anything that matters. If you want to see the difference on a live call, how Paytia works walks through it from carrier to gateway.

For the full feature set behind these recommendations, see our PCI DSS v4 solution.