“NO LAN CABLE” error on Grandstream? Try this!

(NOTE: If you’re impatient, there’s a TL;DR at the bottom of the post, but it may not make much sense to you without the rest of the information in the post. Skip there at your own risk…)

A bit of backstory…

For many years, I’ve used the venerable Cisco SPA508G IP phone as my daily driver on both my home and office desks. Throw in a Cisco SPA500DS digital sidecar, and it’s a golden setup. Plenty of keys for speed dialing, other extensions, etc. and all of your sidecar labeling is controlled from the provisioning server — no more fooling with paper inserts!

As such, I’ve always used that setup as my benchmark when evaluating new IP phones for possible use with my customers. The Cisco equipment is solidly built, reliable, sounds great, and is fairly easy to work with.

A year or so back, I started evaluating more “modern” phones with features my customers would like to see, such as color screens, gigabit Ethernet (for passthrough to computers, etc.) I’ve tried phones by Sangoma, Yealink, and probably a few other vendors. The audio quality on the Sangoma, frankly, sucked. I tried to work with them on getting that fixed, to no avail. I can’t remember what happened with the Yealink or others — but in the end, the Cisco setup always ended up on my desk.

Enter Grandstream…

Back in the day, I used to deploy 2-line Grandstream ATAs. There’s probably one or two still in service on my network out there. More recently, I’ve deployed a few high-density (32-48 port) Grandstream ATAs for customers who needed a lot of analog extensions. Thus, I’m at least somewhat familiar with their equipment, and the fact that it has its quirks at times, but is reliable and definitely production-ready.

Long story as to how it happened (that’s for another post!), but I ended up trialing some Grandstream IP phones. My experience was the same: They have their quirks at times, but nothing that’s a show-stopper like some of the other brands I had tried.

As I tell people who ask about phone models: Is the Grandstream a Cisco? No. Is it still on my desk all these months later, used as my daily driver? Yes. I can’t say that about other brands of phones. So, obviously, Grandstream did something to impress me…

Until, the problem…

I started noticing that when I moved my Grandstream phone around on my home office desk (my primary work location, so I use it the most), I started getting a “NO LAN CABLE” error pop up on the display. All of my extensions would lose registration with their respective PBXen, and I couldn’t make or receive calls. Furthermore, if I was on a call when this happened (great when you’re talking to customers!), the audio just… dies. The call still shows up on the screen, timer runs, but you can’t hear them, and they can’t hear you.

To add insult to injury? My phone is powered via Power-over-Ethernet. That’s right — it’s missing its LAN cable, but it’s still powered on.

So, what did I try?

The  LAN cable I was using at the time was a custom cable that I had made years ago for some other project. It may have even been solid, not stranded, cable. Since the problem seemed to occur when I moved the phone, or jiggled the cable near the end, my first idea was to re-end the cable.

That didn’t work.

So, I decided it must be a break in the cable. I cut about six inches off the cable, installed another new end.

That didn’t work either.

I decided to just condemn the cable, and pull another 10-15 feet off my new(er) spool of cable, and start from scratch. Cut myself some slack, threw ends on it, put it into service.

Guess what? That didn’t work, either.

Obviously, it was the phone. Grandstream must have sold me a bum phone with a bad LAN port. No biggie, we have plenty more at the office, I’ll swap it. And I did.

Guess what? That seemed to work at first, but then I noticed the same issue crop up on short order. Same error would pop up.

Now I’m starting to get just a tiny bit disappointed with Grandstream, and pondering how to re-integrate my Cisco stuff into my daily life… I hated the idea — I’ve really started to like this phone, but I can’t have my calls being dropped like that, nor my phone going unavailable.

Then it hit me (and here is the fix…)

The other morning on the way to work, I had an epiphany. What if the problem wasn’t the LAN port… nor the first cable I re-ended twice, nor the new cable I made, nor my job of installing the ends (my success rate in installing ends is rather high, to be honest.) What if the problem was the actual RJ-45 connector I was installing on the cable? What if it was made in some Chinese factory in a land far, far, away, where specifications, standards, and tolerances have never been heard of? And what if Grandstream sources their LAN ports from the same place, who has never heard of these things? And thus you end up with a combination of LAN port and cable that has enough “wiggle room” to allow the data pins (1/2/3/6) to lose connectivity?

Luckily, I had a pre-made 15-foot Ethernet cable with molded ends in my laptop bag. I carry it around in case I need to cable up to a customer’s network, I’ll have a cable with some length to work comfortably. I decided to bust out that cable, connect it between my switch and the phone (same ports on both ends, of course), and guess what? PROBLEM SOLVED!


If you get the “NO LAN CABLE” error, try replacing the LAN cable. If it’s a LAN cable you made yourself, use a store-bought one. If it’s a store-bought one, try one of a DIFFERENT store-bought brand. There’s a decent chance this fixes your problem. (For “why”, read through the rest of the post above…)


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