Saksalaisen Fraunhofer-instituutin fotonisten järjestelmien IPMS-tutkimusyksikkö tuo Li-Fi-teknologian teollisuuskäyttöön ratkaisulla, joka siirtää dataa valon avulla gigabitin nopeudella. Keskeinen lupaus on alle 100 nanosekunnin deterministinen viive, joka tähtää aidosti reaaliaikaiseen langattomaan ohjaukseen.

Autojen äänijärjestelmät ovat kokemassa arkkitehtuurimuutoksen, kun audiosignaalin siirto siirtyy erillisistä kaapeloinneista auton Ethernet-verkkoon. STMicroelectronics esittelee ratkaisua, jossa sama verkko hoitaa sekä ohjauksen, diagnostiikan että korkealaatuisen audion ilman erillisiä audioväyliä.

Perinteisesti auton audio on kulkenut dedikoiduissa järjestelmissä, kuten Automotive Audio Bus (A2B) -väylässä. Syynä on ollut äänen erittäin tiukka ajoitusvaatimus. Jo noin viiden millisekunnin viive-ero kaiuttimien välillä riittää siirtämään äänen kuuntelijan mielessä väärään suuntaan, ja kahden millisekunnin heitto voi rikkoa koko stereokuvan. Vielä kriittisempi tekijä on jitter eli viiveen vaihtelu, sillä jo mikrosekuntien heilahtelu aiheuttaa vaihevirheitä ja heikentää äänenlaatua selvästi.

Tämä selittää, miksi tavallinen Ethernet ei ole aiemmin soveltunut audion siirtoon. Verkkoliikenteessä paketit voivat viivästyä muun datan takia, eikä ajoitus ole deterministinen. ST:n mukaan tämä rajoite voidaan nyt ylittää viemällä ääni suoraan Ethernetiin.

Yhtiön Stellar G6 -autopiiri tuo audiolle laitteistotason tuen Time-Sensitive Networking -tekniikalle, joka varaa verkosta aikakriittiselle datalle omat siirtoikkunansa ja synkronoi koko järjestelmän yhteiseen kelloon. Näin audiodata saapuu täsmälleen oikeaan aikaan ilman vaihtelua.

If you’ve ever bought a suspiciously cheap Ethernet cable from an online listing, there’s a decent chance you’ve encountered Copper Clad Aluminum. Better known as CCA, it’s exactly what it sounds like—an aluminium conductor with a thin skin of copper deposited on the outside. Externally, cables made with this material look largely like any other, with perhaps the only obvious tell being that they feel somewhat lighter in the hand.

CCA is cheaper than proper copper cabling, and it conducts signals well enough to function in an Ethernet cable. And yet, it’s a prime example of corner-cutting that keeps standards bodies and professional installers up at night. But just how dangerous is this silent scourge, found lurking in so many network cabinets around the world?

Everything you need to know about CCA is in the name—it refers to an aluminium wire with a thin copper cladding, typically applied through a die extrusion process. The reasoning behind this exploits a real physical phenomenon called the skin effect, wherein higher-frequency AC signals tend to travel along the outer surface of a conductor. The idea goes that since most of the current moves through the outer copper skin layer anyway, the less-conductive aluminium core doesn’t unduly impact the wire’s performance. Using copper-clad aluminium wiring is, in theory, desirable because aluminium is much cheaper than copper, which can really add up over long cable runs. Imagine you’re wiring a building with with hundreds of miles of Ethernet cabling, all with eight conductors each—the savings add up pretty quickly.

There’s a problem with CCA cabling in these contexts, though. Due to prevailing cabling standards, any cable made with CCA is technically not even a real Ethernet cable at all. The relevant documents are unambiguous.

ANSI/TIA-568.2-D requires conductors in Category-rated cable to be solid or stranded copper. No other materials are acceptable, and thus CCA is explicitly excluded from use in Category cable applications. A cable with CCA conductors cannot legitimately carry a Cat5e, Cat6, or any related designation under any circumstances. Similarly, ISO/IEC 11801 has the same requirement. The U.S. National Electrical Code also states that conductors in communications cables, other than coaxial cable, shall be copper. This isn’t a suggestion or a best practice; it’s the letter of the code. Anything lesser is simply not allowed.

CCA cabling can be hard to detect, particularly where a manufacturer has intentionally hidden the fact that the inferior wiring is used. One way to be sure is to strip a wire and scrape away at the copper to see if there’s aluminium lurking inside.

The simple fact is that regulators demand a certain level of quality for communications cable, and CCA just isn’t it. In the specific case of Ethernet cabling, it is worth noting that the skin effect that makes CCA construction useful in other applications doesn’t really apply. That’s because the skin effect is frequency-dependent, and so it doesn’t apply to DC power as used in Power over Ethernet. In fact, the DC resistance of a CCA conductor of the same gauge is roughly 55% higher than copper of the same gauge. CCA cables also tend to be less flexible and more brittle than the proper all-copper equivalent. These are fundamental physical ways in which CCA doesn’t measure up to scratch. These differences aren’t enough to stop the cables working for their intended purpose in many cases, but it’s part of the reason that standards organizations mandate pure copper and nothing less.

The problem that stems from this is that installing CCA communications cable in a building can make the installation non-compliant and potentially even illegal in jurisdictions that adopt these relevant standards. Much of the concern comes down to fire ratings and insurance concerns. For example, the UL 444 standard lays out the requirements for cables to meet the CM, CMR, CMG, and CMP fire ratings you see printed on legitimate cable jackets. These rules require copper conductors. Thus, CCA cable cannot carry a valid UL listing and any install using it will not be compliant with fire safety regulations. A building with such cable installed would be potentially liable to have any insurance invalidated for not meeting basic code requirements. Any contractor installing such cable could be liable in turn.

Grabbing a cigarette lighter can also help determine if given cabling is pure copper or copper clad aluminium.

The question is, though—are CCA cables actually a real-world fire risk? That is harder to answer. The common concern is that a tightly-wrapped bundle of CCA Ethernet cables running Power over Ethernet could get hotter than intended due to increased resistance, eventually overheating, melting, or catching alight. With that said, we are yet to see any grand examples of buildings catching fire and burning to the ground because of CCA cabling. Such cables might not be to spec, and they might not do as well when used for Power over Ethernet due to their higher resistance, particularly over longer runs. However, issues are likely to be more related to insufficient power delivery rather than severe overheating. Where there’s no smoke, there usually isn’t fire. There would be plenty of photos online of melted CCA cables being pulled out of smoking rubble if this was occurring on the regular.

Ultimately, if you’ve got a CCA cable or two running around your house, you probably don’t have a lot to worry about. They might not survive as well as a proper copper cable, and they might be a little dodgy on long runs with PoE equipment, but they aren’t just going to burst into flames at the drop of a hat.

Ethernetin uusin kehityssuunta ei tähtää suurempiin nopeuksiin vaan pienempään ja yksinkertaisempaan toteutukseen. Single Pair Ethernet mahdollistaa tiedonsiirron yhdellä johdinparilla ja tuo Ethernetin suoraan kenttälaitteisiin, joissa ovat tähän asti hallinneet CAN ja RS-485.

10BASE-T1S -toteutuksessa nopeus jää 10 megabittiin sekunnissa, mutta vastineeksi saadaan yksinkertaisempi kaapelointi, pidempi kantama ja mahdollisuus rakentaa monipistelähtöisiä verkkoja ilman perinteistä kytkinarkkitehtuuria. Tämä tekee teknologiasta relevantin erityisesti teollisuuden sensori- ja ohjausverkoissa, joissa kaapelointi ja häiriönsieto ratkaisevat enemmän kuin datanopeus.

Arrow Electronicsin yhdessä Microchip Technologyn, Bournsin ja Amphenolin kanssa esittelemä referenssialusta keskittyy juuri näihin käytännön kysymyksiin. Ratkaisun ytimessä on Microchipin LAN8670-PHY sekä IEC 63171-6 -standardin mukainen liitin, mutta huomio kohdistuu erityisesti signaalin eheyteen. Bournsin integroitu magnetiikka, joka yhdistää erotusmuuntajan ja yhteismuotokuristimen, on kriittinen osa kokonaisuutta.