Quick answer: For 2026 Iris Information Technology formalised a four-gate quality programme covering the whole build: incoming component inspection with a documented AQL sampling plan, automated optical inspection after SMT, 100% functional test of every unit, and a 72-hour burn-in on powered assemblies before packing. This article sets out what each gate actually checks, the standards behind them, and the failure data that justified adding burn-in to the line.
Why a formal programme, and why now
Iris has held national security certification for its intercom products (see the certification announcement), and has been building intercom systems in Shenzhen since 2016. But certification proves a design passes a test; it does not prove that unit number 4,000 leaving the line in eighteen months behaves like unit number 40.
The 2026 programme exists to close that gap. It is a manufacturing-process commitment, not a product announcement, and it applies to the digital, two-wire and analogue lines alike.
Gate 1: incoming inspection, on a sampling plan
The cheapest defect to fix is the one caught before it is soldered. Component-level escapes — a mis-marked capacitor, a batch of connectors with out-of-tolerance contacts, an RFID reader module with a weak antenna — are the failures that surface in the field as intermittent faults and consume disproportionate support time.
Our incoming gate runs to a documented sampling plan rather than ad-hoc checking. The reference standard is ANSI/ASQ Z1.4, the acceptance-sampling system widely used in electronics manufacturing to derive sample sizes and accept/reject criteria from batch size and a chosen AQL.[1] It is maintained by the American Society for Quality and published jointly with ANSI; the current edition is ANSI/ASQ Z1.4-2003 (R2018).[2] In practice that means:
- Critical attributes — anything affecting electrical safety or mains isolation — are inspected at zero-acceptance: one defect rejects the lot.
- Major attributes — function-affecting dimensions, contact resistance, markings — run to a tighter AQL.
- Minor attributes — cosmetic issues invisible after assembly — run to a looser AQL, because inspecting to zero on cosmetics is a poor use of inspection capacity.
Every lot gets a traceability record. When a field return arrives with a serial number, the component lots that went into it must be findable, or the inspection data is just paperwork.
Gate 2: AOI after SMT, then functional test
Surface-mount assembly is where the majority of latent defects are created, and most of them are invisible to the eye: insufficient solder on a fine-pitch pin, a tombstoned passive, a component shifted by half a pad, a solder bridge under a QFN that only shows under thermal cycling.
Automated optical inspection compares each board against a golden reference image and flags deviations. It catches the geometric defects reliably — placement offset, missing component, polarity, solder volume. It does not catch electrical defects that look correct: a cracked joint inside a via, or a wrong-value part that is correctly placed.
That limitation is why AOI is a gate and not a solution. The IPC-A-610 standard for acceptability of electronic assemblies defines the workmanship criteria that inspection is measured against, and the Global Electronics Association explicitly notes that the standard is a collection of visual quality acceptability requirements and does not provide criteria for cross-section evaluation.[3] AOI is one tool for meeting those criteria, not a substitute for the rest.
What our functional test adds
After AOI, every board gets a functional test — not a sample, every unit. For an intercom door station or indoor monitor that means, at minimum:
- Power-up and boot, with current draw inside a defined window
- Camera capture at the specified resolution, checked for dead or stuck pixels
- Two-way audio path, including the microphone and speaker at both ends
- Network link, address acquisition and a call placed to a test peer
- Door-release relay operated under load and confirmed to drop out cleanly
- RFID reader reading a known credential at the rated distance
Environmental test, on a sample
Functional test at room temperature proves the unit works in the factory. For outdoor door stations, the sample from each production batch goes into a thermal chamber across the rated range, and into an IP65-rated water spray test. The analogue door station line and the digital outdoor units share the same enclosure philosophy: IP65 or better for exposed entrances.
Ingress-protection test methods and their ratings are defined by IEC 60529; IP65 means dust-tight and protected against water jets from any direction.[4] Note that IP65 does not mean submersible — an important distinction for anyone installing a door station on a low-level entry where standing water is possible.
Gate 3: 72-hour burn-in
This is the gate we added in 2026, and the one the failure data justified.
The logic is standard reliability engineering. A population of electronic assemblies follows a bathtub curve: a period of higher failure rate in early life, a long flat period, then wear-out. Infant mortality is caused by manufacturing defects — marginal solder joints, contaminated die, out-of-tolerance parts — and its signature is failures that cluster in the first tens of hours of operation. The IPC-A-610 standard's own terminology reflects this: a "process indicator" condition is one that, while not a defect, signals that a process is drifting and requires attention before it produces defects.[5]
If those units fail in the factory, they cost a replacement board. If they fail after shipping to a distributor in Europe, they cost a return shipment, a site visit, a technician's day, and the client's confidence. Burn-in moves the failure to the cheapest place to fix it.
What burn-in actually does
Units are powered and run at elevated ambient temperature with a repeating call cycle, camera streaming and periodic door-relay operation. Any unit that fails, resets spontaneously, or shows drift in current draw is pulled and analysed rather than reworked and returned to the line.
The cost, stated honestly
72 hours of powered operation per unit is not free. It consumes rack capacity, floor space, energy and production time, and it extends the interval between an order and a dispatch. Two things make it worthwhile here:
- The product is field-serviceable only at significant cost. A door station 20 m up a building riser is not a bench instrument. The cost asymmetry between factory failure and field failure is large.
- The product is sold through distributors, not directly. A distributor who experiences infant mortality stops specifying the line. Reputation, not the burn-in rack's electricity bill, is the asset being protected.
For high-volume, low-unit-cost accessories, burn-in is not justified and we do not apply it across the board — see the accessories range for the components that ship on the standard test regime.
Gate 4: packing, documentation and traceability
The last gate is the one that quietly determines whether returns are diagnosable.
- Serial number to test record. The unit's serial traces back to its functional test result, its burn-in run and the component lots it consumed.
- Firmware version recorded at packing. Otherwise a field comparison is meaningless.
- Documentation pack per consignment, with the declared firmware support period stated in the order paperwork.
- Export packing to the shipping mode. Ocean freight for intercom equipment is subject to container humidity, so moisture barrier packing matters for anything with an exposed PCB.
What the programme means for a specification
Three practical consequences for anyone writing the quality section of a tender:
- Ask for the sampling plan, not the certificate. "We do incoming inspection" is not auditable. "ANSI/ASQ Z1.4, AQL 0 for critical, AQL 1.0 for major" is.
- Ask what the burn-in duration is and whether it is powered. Some suppliers report burn-in that is storage in a warm room. That tests almost nothing.
- Ask for the traceability scope. Serial-to-test-record is the difference between a diagnosable return and a warranty argument.
Frequently asked questions
Does 72-hour burn-in mean a delay on every order?
It adds three days to the manufacturing lead time. For container-scale orders this is absorbed into the production schedule; for small urgent orders it is visible. If a project has a hard date, tell us at the quotation stage and we will plan the line slot around it.
Is every unit burned in, or a sample?
Every powered assembly in the digital, two-wire and analogue intercom lines. It is a sample only for low-cost passive accessories.
What happens to a unit that fails burn-in?
It is pulled from the line and analysed to root cause. If the cause is a component lot, the whole lot is quarantined and the affected units already built are re-screened. Rework-and-return without analysis defeats the purpose of the gate.
Which standards does the programme reference?
ANSI/ASQ Z1.4 for acceptance sampling, IPC-A-610 for electronic assembly workmanship, and IEC 60529 for ingress protection ratings. Product-level safety and certification requirements are handled per market.
Can we audit the line?
For distribution agreements and larger projects, yes. Contact us with your requirement and we will arrange it. General company background is on the about us page.
Where this goes next
The next step is closing the loop — feeding field-return data back into the incoming acceptance criteria, so an AQL that is too loose on a particular component tightens before it becomes a pattern rather than after. That requires returns to actually reach us with serial numbers intact, which is partly a logistics problem and partly a matter of distributors knowing the traceability is worth using.
If you distribute intercom equipment and want to participate in that feedback loop, our FAQ covers the standard commercial questions, and the technical detail belongs with the engineering team via our contact page.
References
- American Society for Quality, "ASQ/ANSI Quality Standards Z1.4 & Z1.9" — acceptance-sampling system for inspection by attributes, providing tightened, normal and reduced plans at a specified AQL.
- ASQ / ANSI, ANSI/ASQ Z1.4-2003 (R2018): Sampling Procedures and Tables for Inspection by Attributes — current edition, published by the American Society for Quality.
- Global Electronics Association (IPC), "Meet Your Standards" — IPC-A-610J, Acceptability of Electronic Assemblies: visual quality acceptability requirements; does not provide criteria for cross-section evaluation.
- International Electrotechnical Commission, "IP ratings" — IEC 60529 classification of degrees of protection provided by enclosures. IP65 = dust-tight, protected against water jets.
- OWASP, OWASP Internet of Things Project — component-quality and lifecycle risks in connected device manufacture.