{"id":537,"date":"2026-09-29T01:16:42","date_gmt":"2026-09-28T17:16:42","guid":{"rendered":"http:\/\/www.isabellahruby.com\/blog\/?p=537"},"modified":"2026-09-29T01:16:42","modified_gmt":"2026-09-28T17:16:42","slug":"what-is-the-termination-return-loss-of-coaxpress-cable-4ed5-a001f5","status":"publish","type":"post","link":"http:\/\/www.isabellahruby.com\/blog\/2026\/09\/29\/what-is-the-termination-return-loss-of-coaxpress-cable-4ed5-a001f5\/","title":{"rendered":"What is the termination return loss of CoaXPress Cable?"},"content":{"rendered":"

Hey there, if you\u2019ve ever worked with CoaXPress (CXP) cables\u2014whether you\u2019re a systems integrator, machine vision engineer, or just someone troubleshooting a wonky image feed from a high-speed camera\u2014you\u2019ve probably heard the term \u201ctermination return loss\u201d thrown around. At our CXP cable shop, this is one of the first specs we dive into when helping customers pick the right cable for their setup, and honestly, it\u2019s way more important than a lot of folks give it credit for. Let\u2019s break this down like we\u2019re chatting over a coffee (no stuffy engineering jargon, promise). CoaXPress Cable<\/a><\/p>\n

<\/p>\n

First off, let\u2019s get the basics straight. CoaXPress is that super popular cable standard for machine vision, industrial imaging, and even some industrial automation stuff, right? It carries both high-speed data (up to 12.5 Gbps per lane these days), power for accessories, and even control signals all over a single coax. That\u2019s magic, but it also means the signals are bouncing back and forth like drunk ping pong balls if things aren\u2019t set up right. Return loss is how we measure that bouncing. Think of it this way: when you send a signal down the cable, some of it should hit the end (the device, like a camera or frame grabber) and stop there\u2014no bouncing back. The part that bounces back is the \u201creturn signal.\u201d Return loss is just how small that bounced signal is compared to the original one.<\/p>\n

Now, termination return loss specifically? That\u2019s the return loss you get when the cable is properly terminated<\/em> at both ends. Wait, \u201cterminated\u201d means the end device has a resistor that matches the cable\u2019s impedance\u2014for CXP, that\u2019s almost always 75 ohms, same as old-school broadcast coax. If the termination is off (like no resistor, or the resistor is 50 ohms instead), that bounced signal gets way bigger, and that messes with your data. Termination return loss is the measure of how well that termination is working to kill those bounces.<\/p>\n

So why should you care? Let\u2019s say you\u2019re running a CXP cable for a 5Gpixel camera on a production line. If the termination return loss is bad, those bounced signals show up as noise in your image\u2014blurry lines, pixel glitches, maybe even dropped frames. We\u2019ve had customers come to us saying their new cable kit was causing random camera dropouts, and nine times out of ten, the termination return loss was too high (meaning too much bounce). It\u2019s not just a \u201clab spec\u201d either; it\u2019s what keeps your machine vision system running smooth when you\u2019re cranking those high data rates.<\/p>\n

Now, what\u2019s a \u201cgood\u201d termination return loss number for CXP? Let\u2019s keep this real. The official CXP standard (from the CoaXPress Industry Association, yeah, that\u2019s a real group) sets requirements, but in the wild, we see two main specs that matter: near end (within the cable itself) and far end (at the device connection). For CXP 6 or CXP 12, which are the common high-speed modes these days, we\u2019re talking around -20 dB to -25 dB at the frequency bands we use (CXP signals go up to 6.5 GHz for CXP 12, right?). Wait, decibels can be tricky\u2014negative numbers here mean the bounced signal is smaller than the original. So a -25 dB return loss means the bounced signal is 1\/316 of the original; -20 dB is 1\/100. So lower (more negative) is better, because that means less bounce. If it drops below -15 dB, that\u2019s when you start seeing issues\u2014we usually flag cables with that as \u201cmarginal\u201d and don\u2019t send them out for critical applications.<\/p>\n

But here\u2019s the thing: termination return loss isn\u2019t just a cable thing. Wait, I know, I\u2019m a cable supplier, but I won\u2019t lie to you. The cable\u2019s connectors matter just as much, and how you terminate the ends matters too. A lot of cheap CXP cables out there have crimped connectors where the shield isn\u2019t seated right, or the center pin is crooked\u2014 that kills termination return loss faster than anything. We use crimp-and-solder connectors for all our cables, not just crimps, because it gives a tighter, more consistent connection. We also test every single cable we ship for termination return loss on a vector network analyzer (VNA)\u2014not just a visual check. We had a customer once tell us a cheaper brand\u2019s cable worked in their test lab but failed on their factory floor, and when we tested the same length, our cable had a steady -22 dB return loss, theirs was jumping between -12 and -18 dB because of loose connectors.<\/p>\n

Another big factor is cable length. Wait, does length affect termination return loss? Yeah, to a point. For CXP cables, up to 20 meters is standard, but some folks run 50 meters (though we never recommend that for CXP 12, max is 25). The longer the cable, the more the signal weakens, so the return loss gets a tiny bit worse\u2014we see about 1 to 2 dB drop per 10 meters, but that\u2019s totally manageable as long as the initial spec is good. The key is that even at max length, the termination return loss doesn\u2019t dip below that -15 dB threshold. We test every length we make\u2014from 1 meter up to 25 meters\u2014so you don\u2019t have to guess.<\/p>\n

What causes bad termination return loss? Let\u2019s list the usual suspects, since that\u2019s what we deal with daily:<\/p>\n

    \n
  1. Bad connectors: as I said, loose crimps, misaligned center pins, shield not connected. We\u2019ve pulled apart a returned cable that looked fine but had a center pin bent just enough to throw impedance off by 5 ohms\u2014enough to kill return loss.<\/li>\n
  2. Cable core: if the dielectric (the plastic between center pin and shield) is inconsistent thickness, that messes with impedance, which ruins termination. We use high-density PE dielectric, not cheap foam, because it\u2019s way more consistent.<\/li>\n
  3. Poor shielding: CXP relies on the shield to keep signals from leaking, and also to maintain impedance. If the shield has gaps or is made of thin wire, it doesn\u2019t match the 75 ohm spec, so return loss goes to crap. Our cables have dual shielding: foil plus braid, 95% coverage minimum.<\/li>\n
  4. Termination at the device: wait, even if your cable is perfect, if the frame grabber or camera has a bad termination resistor, you\u2019ll still get bounce. That\u2019s not a cable issue, but it\u2019s something we always help customers troubleshoot\u2014we don\u2019t want them blaming our cable when it\u2019s a device setting.<\/li>\n<\/ol>\n

    Now, let\u2019s talk real-world examples, because that\u2019s what our customers care about. Last quarter, a automotive inspection company hit us up. They were using a 15-meter CXP 12 cable for their line that checks car body panels\u2014super critical, no glitches allowed. Their original cable had constant pixel noise, and when they measured it, the termination return loss was -11 dB. We sent them our standard 15-meter CXP 12 cable, tested, and their return loss hit -23 dB. The noise was gone, and their inspection rate went up by 10% because they didn\u2019t have to stop to fix glitches. Another customer was running a 20-meter cable for a food packaging line, and their camera was dropping frames randomly on long runs\u2014turns out the cheap cable they were using had return loss of -14 dB at 20 meters, and ours was -21 dB, so no more dropouts.<\/p>\n

    At our shop, we don\u2019t just slap a CXP label on a cable and send it out. We have a full testing station where every cable gets a VNA sweep from 10 MHz up to 7 GHz, specifically checking termination return loss across the entire CXP frequency band. We log that test data for every cable\u2014if you need it, we can send it to you, no questions asked. We even have a few \u201cproblem cables\u201d in our office that we\u2019ve tested bad, just to show customers what not to buy (they make good doorstops, honestly).<\/p>\n

    Wait, a quick myth I need to bust: some people think return loss is only important for super high-speed CXP 12, but no\u2014even CXP 1 (which is 1.25 Gbps) can have issues if return loss is bad. It\u2019s just that at higher speeds, the signals are tighter, so bounce is more noticeable. But for any CXP setup, termination return loss is a baseline spec you shouldn\u2019t skip. If your cable has a return loss below -18 dB, that\u2019s probably fine for short runs (under 5 meters) but not for longer or higher-speed setups.<\/p>\n

    Here\u2019s the thing: we\u2019re not just a supplier. We\u2019re engineers too, and we deal with the same headaches you do when your machine vision system goes down at 2 a.m. because of a bad cable. That\u2019s why we designed our cables to keep termination return loss consistent, no matter the length. We don\u2019t cut corners on connectors or shielding, because we know the cost of downtime is way higher than the extra we charge for a good cable.<\/p>\n

    If you\u2019re shopping for CXP cables, don\u2019t just look at price. Check the termination return loss spec. Ask the supplier if they test every cable (or at least sample them\u2014though we test 100%). If they say \u201cwe meet the standard,\u201d that\u2019s a start, but ask what their actual tested numbers<\/em> are. The CXP standard is a minimum, but good suppliers will beat that by a few dB to give you headroom.<\/p>\n

    <\/p>\n

    At the end of the day, termination return loss is the unsung hero of CXP cable performance. It\u2019s not flashy, it\u2019s not a marketing buzzword, but it\u2019s what keeps your images sharp, your frames steady, and your production line running. If you\u2019re tired of dealing with glitchy cables, or you\u2019re putting together a new CXP setup and want to make sure you get the right cable on the first try, hit us up to talk through your needs. We can help you pick the right length, confirm the termination return loss will work for your application, and make sure you don\u2019t have to troubleshoot cable issues down the line. You don\u2019t have to waste time testing cheap cables or dealing with random failures\u2014we\u2019ve got you covered.<\/p>\n

    USB Cable<\/a> If you want to learn more about CXP specs or termination return loss, here are the references we use daily:<\/p>\n

      \n
    1. CoaXPress Industry Association. (2021). CoaXPress v2.1 Specification.<\/li>\n
    2. Pozar, D. M. (2012). Microwave Engineering (4th ed.). John Wiley & Sons.<\/li>\n
    3. Machine Vision Association of the Automation Technology Federation. (2020). CXP Cable Performance Guidelines for Industrial Applications.<\/li>\n<\/ol>\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 there, if you\u2019ve ever worked with CoaXPress (CXP) cables\u2014whether you\u2019re a systems integrator, machine vision … What is the termination return loss of CoaXPress Cable?<\/span>Read more<\/a><\/p>\n","protected":false},"author":305,"featured_media":537,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[500],"class_list":["post-537","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-industry","tag-coaxpress-cable-4f2a-a03649"],"_links":{"self":[{"href":"http:\/\/www.isabellahruby.com\/blog\/wp-json\/wp\/v2\/posts\/537","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.isabellahruby.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.isabellahruby.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.isabellahruby.com\/blog\/wp-json\/wp\/v2\/users\/305"}],"replies":[{"embeddable":true,"href":"http:\/\/www.isabellahruby.com\/blog\/wp-json\/wp\/v2\/comments?post=537"}],"version-history":[{"count":0,"href":"http:\/\/www.isabellahruby.com\/blog\/wp-json\/wp\/v2\/posts\/537\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/www.isabellahruby.com\/blog\/wp-json\/wp\/v2\/posts\/537"}],"wp:attachment":[{"href":"http:\/\/www.isabellahruby.com\/blog\/wp-json\/wp\/v2\/media?parent=537"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.isabellahruby.com\/blog\/wp-json\/wp\/v2\/categories?post=537"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.isabellahruby.com\/blog\/wp-json\/wp\/v2\/tags?post=537"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}