Author Topic: I.P. Daley, I need your help. (Problems with Modem/Router)  (Read 3725 times)


  • 5 O'Clock Shadow
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I.P. Daley, I need your help. (Problems with Modem/Router)
« on: October 05, 2013, 02:48:14 PM »
I live in Tempe, Arizona and use Cox Communications for my internet - I'm paying $40/month for 25mbps (is that bit or bytes..?)

I have a Motorola Modem ( is roughly the same) and a Belkin N150 Router ( I got mine from Target, thus the link).

So, I've been having very spotty service - I called into the Tech Support line for Cox, they say that everything looks fine from their end and that they don't know what's wrong. I had a Service Technician come out back in July when I first got the service and he checked the wiring, fiddled with it a bit and added in a new co-ax line downstairs, and this is where the Modem/Router are set up. I have a laptop and a newly built desktop in my room upstairs and my roommate uses a laptop, all wireless.

Even when I bypass the router, completely unplug it and turn it off, and plug my desktop straight into the Modem, my service is horrible...maybe that's because my modem is ancient? The tech support guys say it's fine, but I got that as a hand-me-down from my Grandma in Iowa (me trying to save money).

What I'm wondering is: How do I get the most out of the service I am paying for? Should I go with a directly from Cox Communications and hope that helps? I am just very frustrated at this point, because I have to reset my modem/router about every 15 minutes and the download speeds will rev up for a bit and then crash back down to approx 5bps, yes I mean that low, and even get down to 0bps and stay there, like as I'm writing this I have no internet and will have to wait for it to either come back up or will most likely have to go downstairs and power cycle the setup.

Just looking for advice - if there are articles that would help me, please share. I just want reliable and fast service (who doesn't) that I don't have to mess with every hour. Thank you


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Re: I.P. Daley, I need your help. (Problems with Modem/Router)
« Reply #1 on: October 06, 2013, 09:28:20 AM »
Guardian, most Motorola modems have a diagnostics page located at and should be accessible when plugged into the modem directly or with a router sitting between the two points.

(Important: the above link is clean and points to an internal address on your network, but for the sake of general security best practices, never trust these sorts of internal network links from other people and enter the address into your web browser manually.)

From this address, you can access diagnostic information about your modem. On the left should be a link labeled "Signal" that will give you a pile of numbers. Clearly, you'll want to check these numbers both when the internet connection is working well and when its buggered up. The number ranges to look for can be found here:

(DSLReports is a fantastic resource for technical information regarding internet service providers, amongst other things.)

The information gleaned off of this step will help with troubleshooting with any technician or in trying to isolate the problem yourself.

If the numbers consistently line up on reset but rapidly fall out of spec, you might be looking at a problem with the modem. Troubleshoot further with a Level 2 or 3 Cox phone technician to try and confirm before you buy another modem. Details why later on.

If there's no pattern to when the numbers fall in and out of spec, there's noise on the line. Before chasing down the remainder of the rabbit hole on this one, jiggle the coax feeding into the modem while updating the page, if it feels loose or you're getting noise issues, the noise problem is in the modem itself due to a damaged connector. If you've got good connectors and cable from the modem to the demarcation point (which it sounds like you have), then the line noise issue is somewhere between the DMARC and your local neighborhood cable node, though most likely somewhere along the feeder cable end (the dedicated run to your place) as if it was farther back, there'd be problems with other customers in your area as well.

If there's no major deviation on the power levels and signal to noise ratio (SNR) from desired spec between a good and bad connection (unlikely, if I'm to listen to my gut - but I'm including it for completeness), then let's keep going down the line.

I trust (and hope) for the sake of simplicity that you're running Windows? If so, this next step will be really easy for you. Download and run PingPlotter on a two minute cycle basis (or so) pinging one of the major domains like Google (or any other domain listed as an option) for 24-48 hours and save the logs. Usually, running it that long isn't necessary unless the problem is intermittent. If the problem area is blatantly obvious early on and consistent, you probably don't need more than an hour or so worth of data.

PingPlotter is useful for situations where you need to work out where any connectivity issues are located. If there's a problem with either your equipment or theirs somewhere along the line, PingPlotter should highlight the weak spot. If the modem's going a little silly, you'll see ping lag starting between you and your cable modem. If it's a possible local noise issue between the node and yourself, it'll show up in the first leg between the modem and the first Cox node. If it's further down the line in their infrastructure, it'll show up as a major lag point at that location. The Cox tech should be able to utilize the info to locate where the problem rests if it's outside of the immediate area and unrelated to your modem and the local wiring... they'll likely be surprised to see such useful information, especially from an end user, but whenever I've needed to bust out PingPlotter to resolve connectivity issues, the problem usually gets fixed within a couple days once I've proved it's not my end but theirs, and where roughly their problem is.

If you're running Linux or OSX, I've honestly never found an equal that anybody can run and so easily understand the output with on either platform. The good news is, PingPlotter runs great under WINE. The bad news is, you have to run WINE with root privileges so it works, which is a little nerve-racking to do. If you have a Windows box in the house, just run it off that.

I've gone through all possible troubleshooting points in hopes of covering all the bases for you and for future knowledge if needed, but truthfully I suspect you won't need them. My gut's telling me that the modem might be flaking out given the issue and pattern described along with the possible age. The problem is, even with the higher quality build on the Motorola/Arris modems (Google sold Moto's cable modem division to Arris about a year back, but the transition has only recently become official), these things are not built to last for a long time. Capacitors dry out and go bad, MOSFETs get damaged from power surges, it's basically part of the bigger planned obsolescence cycle. They can't keep making money off you if you don't have a reason to come back and buy the same thing over and over again. The easiest way to extend your networking devices' potential lifespans is to power them off of a UPS. Higher-end APC devices (not the small office/home office models) are industry Gold Standard, but CyberPower's AVR series devices are a good secondary option as the build quality is good, the power is relatively clean (for the money spent), and the lead acid batteries are user replaceable.

Technically, $5 or less of a few electrical components, a smattering of electrical engineering knowledge and a little practice with a soldering iron could possibly fix the issue if it's capacitor failure on the modem, but that's a bit beyond a lot of folks comfort zones... if you're needing to ask me for troubleshooting help, I'm not going to expect you to try and fix it. I just bring it up as a point to be aware of: most electronic waste with equipment like this is avoidable, and that point of avoidance usually costs less than a buck to do on the manufacturing end with electrical component selection.

Anyway, back on topic. Honestly, the easiest troubleshooting step would be to swap out with a known good (usually new or confirmed good used) modem. If that fixes it, there's your problem. Unfortunately, cable modems aren't like DSL modems where you just enter in some account details on a new device and swap it out... the modem swap requires a provisioning change on the cable ISP's end to make the device work (which requires calling support), and if nothing changes, now you probably have to go back and re-provision the old modem again if you don't want to own multiple cable modems. This is why I recommend trying to troubleshoot further with a high level Cox phone tech with the additional information you can gain using this information before running out and just buying another modem, but if you're feeling confident that it might be the modem yourself, the easiest fix is to likely just buy a new one.

As for purchasing another modem, never buy the modem directly from Cox, they'll gouge you on the price. Any DOCSIS 2 or DOCSIS 3 modem will work and be supported. Motorola/Arris Surfboard modems are probably the most reliable you'll be able to get. If you're buying new, try not to spend more than $50 on a DOCSIS 2 model, and more than $80 on a DOCSIS 3 one. Keep your router separate from your modem, as you have fewer failure points in a single device, and replacement of individual components will be cheaper than multifunction when they invariably come to their failure point.

I'm not sure there's much else rattling around in my melon that will be of use, but this should at least empower you sufficiently to try and isolate the problem with confidence and hopefully resolve it... and if you don't mind, I may recycle it into a blog post for obvious reasons. Finally? If the info helped, you can always repay the kindness through my website if you're inclined... it'll be appreciated, but it's by no means mandatory. I help because I can.

Good luck, Guardian. Keep me posted.


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Re: I.P. Daley, I need your help. (Problems with Modem/Router)
« Reply #2 on: October 06, 2013, 11:29:38 AM »
Thanks for the info.  I will definitely have to try it out on one of the days when my cable connection seems slower than molasses, for no discernable reason.

Might I add one possible (that is, it happened to me, but I don't know how common it might be) cause?  I have several machines on the router, but normally only one is powered on.  I was experiencing really slow file transfer speeds (and slow web in general, but I had no way of knowing whether that was on my side).  Turns out that having one of the desktops plugged in to the router but not powered on brought everything down to either 10 or 100 mbs, instead of the normal Gbit ethernet.


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Re: I.P. Daley, I need your help. (Problems with Modem/Router)
« Reply #3 on: October 06, 2013, 10:23:38 PM »

Guardian, I am over a few miles from you in Gilbert and just switched from Cox (to Century Link). My recommendation for you if you need to get another modem is to try out GoodWill. You may have to find the power cord separately but you can usually find one if you are willing to go to a few stores. For both pieces it should cost you less than $10 (I can often find them under $5). Here is cox's list of approved modems so you can pick off this list (I don't know about you but I find that Tech Support would not work with me at all if I want using one of modems on the list...):

Good Luck!