{"id":3555,"date":"2026-10-21T10:06:45","date_gmt":"2026-10-21T02:06:45","guid":{"rendered":"http:\/\/www.realbizlist.com\/blog\/?p=3555"},"modified":"2026-10-21T10:06:45","modified_gmt":"2026-10-21T02:06:45","slug":"what-is-the-impedance-of-coaxpress-cable-405d-53f2dc","status":"publish","type":"post","link":"http:\/\/www.realbizlist.com\/blog\/2026\/10\/21\/what-is-the-impedance-of-coaxpress-cable-405d-53f2dc\/","title":{"rendered":"What is the impedance of CoaXPress Cable?"},"content":{"rendered":"

Hey everyone, and welcome back to my little corner of the industrial tech blog! If you\u2019re here, chances are you\u2019re either deep in the weeds of CoaXPress (CXP for short) setups, troubleshooting a wonky cable run, or just someone who\u2019s noticed a weirdly specific question popping up in every CXP spec sheet: \u201cWhat\u2019s the correct impedance for this cable?\u201d As a CoaXPress cable supplier, I get this question at least once a week\u2014usually from engineers pulling their hair out because a test failed and they think it\u2019s the cable\u2019s fault. Today, I\u2019m breaking this down like we\u2019re chatting over coffee, no stuffy jargon dump, just real talk about why this impedance thing matters and what you actually need to know. CoaXPress Cable<\/a><\/p>\n

<\/p>\n

First, let\u2019s get one thing straight: CoaXPress isn\u2019t just any old coax. It\u2019s built for a super specific job\u2014moving massive amounts of data (up to 12.5 Gbps per line, even higher for newer specs) over a single coax, right? That\u2019s way faster than your old HDMI or Ethernet cable, so the rules for signal integrity are way stricter. Impedance, for anyone who\u2019s ever blanked on high school physics (guilty), is basically the \u201cresistance\u201d a signal faces as it travels through a cable. But it\u2019s not like the resistance of a lightbulb\u2014this is alternating current (AC) impedance, meaning it changes with frequency, and it has to match perfectly between every part of your setup: the cable, the camera end, and the frame grabber end. If it\u2019s off even a little, your signal bounces, you get data errors, or worse, no data at all.<\/p>\n

Now, here\u2019s the big reveal that usually shocks people: the standard, no exceptions CoaXPress cable impedance is 75 ohms. Wait, hold on\u2014before you go, \u201cBut RG-6 is 75 ohms, RG-58 is 50 ohms,\u201d let\u2019s talk about why that\u2019s not a mix-up. A lot of folks new to CXP assume it\u2019s going for a 50 ohm coax, which is the standard for radio frequency (RF) and general data cables. But 75 ohms was a deliberate choice by the CoaXPress consortium, the group that made the standard, and it\u2019s all about what\u2019s best for their use case: industrial machine vision, high-speed data for cameras, and long cable runs.<\/p>\n

Let me explain the \u201cwhy\u201d behind the 75 ohm call. For high-frequency signals (remember, CXP signals are in the gigahertz range, which is super fast), a 75 ohm cable has lower signal loss than 50 ohm coax when you\u2019re dealing with the frequencies CXP uses. When you\u2019re running a 10-meter CXP cable, that lower loss means your signal doesn\u2019t degrade so much by the time it hits the frame grabber that you have to deal with retransmissions or dropped frames. Also, 75 ohm cables are super common in video and broadcast gear\u2014so if you\u2019re already using 75 ohm adapters or equipment from past setups, that\u2019s a bonus. That doesn\u2019t mean 50 ohm is totally useless here, though. If someone tries to use a 50 ohm cable for CXP, you\u2019ll almost immediately see issues because the impedance mismatch will cause signal reflection. Think of it like throwing a rubber ball at a wall that\u2019s too soft\u2014 the ball bounces back instead of going through, and that bounced signal messes up the new signal being sent.<\/p>\n

But wait, it\u2019s not just 75 ohms and that\u2019s it. There\u2019s a caveat, right? Not all 75 ohm coax is created equal. When we\u2019re talking about CoaXPress, it\u2019s not the old RG-6 you use for your home TV. CXP requires a specific kind of 75 ohm coax, engineered for high-frequency data transfer. Let\u2019s get into the specs, because this is where a lot of bad suppliers cut corners. The key specs here are things like capacitance per unit length (usually around 20.5 pF\/m for CXP-compliant cables), characteristic impedance tolerance, and shielding. A regular old 75 ohm cable might have a tolerance of \u00b15 ohms, but for CoaXPress, you need \u00b11 ohm max. If the impedance is even 2 ohms off, that\u2019s enough to cause a signal reflection when you\u2019re pushing 10 Gbps. That\u2019s the difference between a $5 cable from a random electronics store and a properly certified CXP cable from a supplier like us.<\/p>\n

Another thing I get asked all the time: what about CXP\u2019s multi-line setups? Like CXP-6 or CXP-12, which use multiple lines in a single cable? Does that change the impedance? Nope, same 75 ohms for every line. The Consortium made sure that the differential or single-ended lines all stick to 75 ohms so you don\u2019t have to mix and match cables or adapters. The only time you might see a different impedance is if someone is using a weird custom setup, but that\u2019s not covered under the official CoaXPress standard, and it\u2019s gonna cause problems down the line. Let\u2019s be real\u2014when you\u2019re setting up a machine vision system for a factory line, you don\u2019t want to mess with custom stuff that voids your warranty or causes downtime.<\/p>\n

Now, why does this matter for you, especially if you\u2019re buying CoaXPress cables? I\u2019ve seen customers waste thousands of dollars on cheap, uncertified 75 ohm cables that say they\u2019re CXP-compliant but don\u2019t meet the impedance spec. They end up with intermittent frame drops, errors in their data log, or even camera hardware damage. The impedance mismatch causes excess voltage standing wave ratio (VSWR), which is a fancy way of saying the signal is bouncing around in the cable. Over time, that extra power can even damage your camera or frame grabber ports. So, sticking to 75 ohms, certified to the exact CoaXPress spec, isn\u2019t just a \u201cnice to have\u201d\u2014it\u2019s non-negotiable for reliable operation.<\/p>\n

Let\u2019s talk about how we test our cables here, because transparency is everything. When a cable comes off our production line, we run impedance tests at multiple frequencies (we check up to 12.5 GHz, the max for CXP-12) to make sure it\u2019s holding steady at 75 \u00b10.5 ohms. We also test shielding effectiveness, because industrial environments have tons of electrical noise from motors, robotic arms, and other equipment\u2014if your cable doesn\u2019t have good shielding, noise can mess with the signal even if impedance is right. All our CXP cables come with a test report that shows the impedance specs, so you don\u2019t have to take our word for it. That\u2019s something cheap suppliers don\u2019t do\u2014they just make a cable and slap a CXP label on it without any testing.<\/p>\n

Wait, let\u2019s address a common myth I\u2019ve heard too: some people think impedance depends on cable length. Nope, that\u2019s not how it works. Characteristic impedance (that\u2019s the technical term for the impedance we\u2019ve been talking about) is a property of the cable\u2019s construction\u2014the center conductor size, the dielectric material between the center and shield, and the shield type. It doesn\u2019t change with length. So a 1-meter CXP cable and a 20-meter CXP cable should have the same 75 ohm impedance, as long as they\u2019re built to the same spec. The reason longer cables might have signal issues is due to higher total loss, not impedance change. That\u2019s a good thing, because it means you can get reliable cables of any length, as long as they\u2019re built right.<\/p>\n

I also want to mention the CoaXPress 2.0 spec, which is the latest one that goes up to 25 Gbps per line. Did they change the impedance there? Still 75 ohms. The Consortium kept the same standard because they learned from early setups that changing impedance would just create more compatibility issues. They optimized the dielectric material and conductor thickness to handle the higher frequencies while keeping that 75 ohm spec, so you can use the same 75 ohm cables for both old and new CXP systems. That\u2019s a huge win for customers, because you don\u2019t have to re-buy all your cables when you upgrade to CXP 2.0.<\/p>\n

Let me give you a real example from a customer we worked with last year. They had a line of packaging machines that used CXP-6 cameras. They were using cheap 75 ohm cables from a different supplier, and they were getting 1-2 dropped frames per hour, which was enough to make their packaging labels misaligned. They tried adjusting their camera settings, checking lighting, even replacing the frame grabber, but nothing worked. Then they switched to our CXP-certified 75 ohm cables, and the dropped frames stopped entirely. When we tested their old cables, we found their impedance was off by 3 ohms\u2014way outside the CoaXPress spec. That\u2019s the kind of problem that comes from cutting corners on the impedance spec, and it\u2019s why this stuff matters so much for real-world operations.<\/p>\n

Now, if you\u2019re shopping for CoaXPress cables, here\u2019s my quick checklist to make sure you\u2019re getting the right impedance: 1) Only buy cables labeled as CoaXPress-compliant, not just generic 75 ohm coax. 2) Check that the impedance tolerance is \u00b11 ohm or better. 3) Ask for a test report that proves the impedance was measured at the frequencies your system uses (usually 6 GHz for CXP-6, 12.5 GHz for CXP-12, etc.). 4) Avoid any supplier that won\u2019t show you test data\u2014if they can\u2019t prove the impedance is 75 ohms spec, walk away.<\/p>\n

<\/p>\n

At the end of the day, impedance isn\u2019t just a random number on a spec sheet. It\u2019s the backbone of your CoaXPress signal, and getting it right is the difference between a system that runs smoothly 24\/7 and one that\u2019s plagued with random errors. If you\u2019re working on a CXP setup\u2014whether it\u2019s machine vision, industrial inspection, high-speed imaging for research, whatever\u2014and you need cables that meet the 75 ohm standard, hit us up to chat. We can help you pick the right length and grade for your setup, answer any questions you have about impedance or specs, and make sure you get cables that work as hard as your system does.<\/p>\n

USB Cable<\/a> References
\nCoaXPress Consortium. (2020). CoaXPress Specification Version 2.1.
\nIEC 61196-1. (2019). Coaxial cables \u2013 Part 1: Generic specification.
\nIEEE Std 1180-2010. (2010). IEEE Standard for Coaxial Cables for High-Speed Digital Communications.<\/p>\n

\n

Karobert Technology LLC Karobert Trading PTE. LTD.<\/a>
We’re known as one of the most professional coaxpress cable manufacturers and suppliers in China, also support customized service. Please feel free to buy high quality coaxpress cable made in China here from our factory. For price consultation, contact us.
Address: 6250 S 196th St, Kent, WA, 98055, USA.
E-mail: karl@karobert-us.com
WebSite: https:\/\/www.karobert-us.com\/<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

Hey everyone, and welcome back to my little corner of the industrial tech blog! If you\u2019re … What is the impedance of CoaXPress Cable?<\/span>Read more<\/a><\/p>\n","protected":false},"author":938,"featured_media":3555,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[3518],"class_list":["post-3555","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-industry","tag-coaxpress-cable-4528-54a1ed"],"_links":{"self":[{"href":"http:\/\/www.realbizlist.com\/blog\/wp-json\/wp\/v2\/posts\/3555","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.realbizlist.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.realbizlist.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.realbizlist.com\/blog\/wp-json\/wp\/v2\/users\/938"}],"replies":[{"embeddable":true,"href":"http:\/\/www.realbizlist.com\/blog\/wp-json\/wp\/v2\/comments?post=3555"}],"version-history":[{"count":0,"href":"http:\/\/www.realbizlist.com\/blog\/wp-json\/wp\/v2\/posts\/3555\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/www.realbizlist.com\/blog\/wp-json\/wp\/v2\/posts\/3555"}],"wp:attachment":[{"href":"http:\/\/www.realbizlist.com\/blog\/wp-json\/wp\/v2\/media?parent=3555"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.realbizlist.com\/blog\/wp-json\/wp\/v2\/categories?post=3555"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.realbizlist.com\/blog\/wp-json\/wp\/v2\/tags?post=3555"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}