# How do I know if my modem is working correctly? ++



## Green972 (Mar 8, 2013)

I had a few problems since yesterday, all of a sudden internet stopped working, all modem lights flashing correctly, the only problem was on my modem-connected computer it said my connection was local only(not local and wifi) and the connection icon of two computer and the wheel thing, didn't have the wheel thing, pages showed up as "no connection" some of them said dns server, so I thought it was my ISP, contacted them they said everything is running on their end, I asked them if it could be my modem? may be time for a new one/do I have to replace it? they said that could probably be it.


So......I went out got a new modem, came home, but now old modem works!! and new modem does not....
no idea why new modem won't work, connected correctly, the only thing I can think of is I have an unsupported OS-Vista, if modems need to be "installed" or "registered" through a disk, maybe that disk is not compatible with my OS, is that possible?

My ISP said all modems are compatible with the service provider I have so it was not that kind of problem.

But what the heck just happened! I've rebooted it several times last night and today and all of a sudden old modem works again? what about the other thousand times I've rebooted it? why didn't it work then?

I'm sorry for the long post but I don't know what's wrong, how can I find out for sure if my old modem is still faulty or if it's working perfectly?
How are you even supposed to know when your modem dies...?

I asked my ISP how long do modems usually last they said you should replace every 7 years....is that true? how are you supposed to know when it has problems?

I really need some help...
I have no idea what's going on.. why is old modem working all of a sudden/does it still have problems?
and why is my new modem not working? could an old OS be a cause/with registration through disk? I have no idea..

(look's like I'm going to have to sell my new modem now because store won't accept returns and company is somewhere overseas ugh.....$80


/Thank you for help!


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## alpenadiver (Jul 31, 2007)

While you were talking to your ISP, did you register your new modems MAC Address with them? It will not work until you do.

You can always check the logs, the SnR (signal to Noise Ratio), and Power Levels, on a Motorola / Arris modem the IP Address is 192.168.100.1

As for a 7 year lifespan I can't help with, I say Hardware is Hardware it will fail at some point.


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## Green972 (Mar 8, 2013)

No, I did not, they didn't even tell me that's what I had to do, I told them that my current modem may not be working properly, I may have to purchase a new one and I just asked them if all cable modems are compatible with them, they said yes, you just connect it and they should work, that's it! that's all they said. Maybe this is an obvious thing but I'm not so good with these things, I think they should have told me that I need to register the new modem with them, that's kind of important to say, so since they didn't I thought I didn't have to.. I thought after I purchased it that I would have to do the registration through the disk...
/
I'm very frustrated..they are not much help it seems that I have to just figure things out on my own 80% of the time :/
/
Ok, I went into the logs on old modem but to be honest I am not sure how to read them, and what they mean for my modem. Could you help me out with that? /are you able to access it too? or should I copy/paste some screenshots? :/

/So you never know either when your modem will stop working/die? because sometimes with a computer it'll start giving blue screens or start shutting down/have other issues/become outdated etc. there is no way to know that about a modem? that kind of makes it harder to know..
Do the logs ever say if there's a critical problem which might cause possible shutting down/modem dying?

/I just don't know what to do...I guess old modem is working for now..although what if it goes off again? I just thought all modems do is provide internet connection from ISP, so it's just a box because all your internet is coming from ISP..


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## alpenadiver (Jul 31, 2007)

The logs are cryptic at best, a google search of the error helps explain them. Another troubleshooting tip is to check your Signal to Noise Ratio, Upstream Power, and Downstream Power. If you post these,and any errors from the log. I can help you with them.


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## Green972 (Mar 8, 2013)

Yea, the logs are what is worrying me, I'm seeing a LOT of critical errors even today after there is normal connection again....not sure what's going on, if there is still a problem..and what I should do.
Almost all of them are critical errors, I'm very concerned about that.

I just had a thought, since both computers in the house are outdated, could a faulty network card in the computer be causing all these problems(connection issues on all devices?)

I just remembered that my laptop's network card is having problems (will be updating all computers soon) but since network card is having problems could it affect my whole internet connection? is that possible?
heck, just today I turn on my laptop and it's saying there is no OS.....just a black screen..
and my network card was not working so well..
Thankfully after another reboot everything was working fine again, that scared the heck out of me.

But then if that is true, all computers have network cards, so why would only one of them cause a connection error when or if there are still other working cards in other computers? if that is the case.

/
Signal to Noise ratio: 38.2 dB
Upstream/Downstream Power...I don't have that it just says Power Level on my page, 
Power Level: -7.5 dBmV 
"The Downstream Power Level reading is a snapshot taken at the time this page was requested. Please Reload/Refresh this Page for a new reading"

Logs....mostly looking at the day my connection was out. These are all from 1 day, I posted them once but there are LOTS of these same logs I'm seeing again and again.

- Timeout, what does that mean, is that something to worry about? 
- Ethernet link dormant - not currently active
- DHCP WARNING - Non-critical field invalid in response.
- DHCP FAILED - Discover sent, no offer received
- SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing
- No UCD's Received - Timeout
- T1 No Ucd Timeout - Reinitialize MAC...

and today's LOG, 

- Started Unicast Maintenance Ranging - No Response received - T3 time-out


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## alpenadiver (Jul 31, 2007)

Who is your ISP? 
Is this from "The Old Modem"?
What is the Make and Model of both Modems?
Your Computers have nothing to do with your modem not connecting to your ISP.

Power Levels: 
Signal to Noise Ratio, you want to be above 30 dB the higher the better.
Down Stream power: +8dBmV to -8dBmV is the sweet spot
Up Stream power: 40dBmV to 50dBmV
Your readings look to be within spec. The down stream power is close to the lower end (-7.5dBmV) 

Your modem errors, point to your ISP's signal is getting to the modem. 
The fix? 
You call ISP, you will have a Tech come, they will change some coax, maybe splitters. If that didn't fix problem, they will blame your Modem, hand them the new modem they will register it with ISP it may work or may not. If it fails then it is their problem between your modem and the head-end, which they will most likely deny. This may take multiple tech support calls to your ISP, just stay on them until you are satisfied.


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## Green972 (Mar 8, 2013)

Aw man this is really not good, so in the end it's my ISP's problem...their signal, what the heck, they should know this!! that there is a problem..they should be the ones telling me.
Maybe I should switch companies soon. My current ISP is Rogers Cable, been thinking of switching to Comwave or something, maybe a company that deals with just internet.

Rogers CS is not good at all....as from my experience, because there's a lot of people on CS that don't know anything.../ 
I actually had a tech guy come in not long ago maybe a couple years ago, he put a new cable through our house from our tv all the way through to our computer room, stapled it along the walls etc. so somewhere in there there is a problem..it's weird that ISP does not know about this! that frustrates me, they never see my connection errors on their end, what's up with that?

I think I will call a repair guy to come over, check the cable.
All they do is check to see if there is a signal, if there is and internet is working they leave..
I could install new modem but if old one is working again then I don't think it was the modem that was the problem. But try explain it to them..they will tell you otherwise..ugh damn cable companies! one time they also said that if everyone in your area(neighbours etc) are online at once then your internet may go down and be the cause, is that true?
/ I will do my best! if they refuse to do anything I will switch companies..


Yes/ everything I posted logs etc. are from old modem. I only hooked up new modem for a few seconds, then hooked up old modem again and it was working. My new Modem is a Thomson DCM 476 thinking about maybe selling it because I have no use for it if old is working again.
I asked ISP if my modem was working they said everything looks good on their end even when it wasn't working 2 days ago. They said they saw no errors/disconnection during that time....
so much confusion from them.


/so if my modem was not working, online IP address under modem status it would say something like offline?


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## alpenadiver (Jul 31, 2007)

Before you sell the new modem, I would call Rogers Cable and register (Provision) it then try connecting. Your old modem may have failed, if the new modem has issues then you have issues.

A easy way to check your in house cabling, would be to go outside to the termination box on the side of your house, connect the modem to the coax running to the line coming from the street, connect a laptop to the modem see if you have internet. 

If this works then you know the issue is in your house.


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## Green972 (Mar 8, 2013)

How can my modem fail if all of my internet signals are coming from my ISP? that's what I don't get because the modem is just a box, right? the power signals it gives off if they're not good enough they are all coming from my ISP so the box does nothing but sit there. 
Even when I had no internet for 2 days my modem was still lighting up normally like nothing had happened.
I think there may be something off with my cable because there is no other explanation,either my ISP'ers servers were down(which they said were not) or my cable is having issues.
I kept seeing a DNS error when I tried to repair connection on my computers. and the computer icon with the wheel thingy kept saying "local only" which my ISP said was the problem. It was supposed to say "local and internet".

Hopefully I can get an experienced tech guy to come in and see what's up. I will try and see if we have a coax port on the side of our house but immediate connection might not mean everything's fine, I now have connection on my old modem and you would think everything is fine but it wasn't 
3-4 days ago when I had no connection for 2 days out of the blue.

Am wondering if cable needs to be renewed/updated? I think we had that done once actually, /and then repair guy said that if you continue to have problems internet can get weighed down by your neighbors if everyone is on at the same time-is this a thing? can that happen? 
so if that is true then what is the solution for that, get a higher powered internet/modem/cable? or wait it out I think is what he suggested..


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## alpenadiver (Jul 31, 2007)

In post #5 the error is saying the modem isn't receiving any signal from Rogers, in my previous post i said how you can test your internal cabling.

On your computer, you will receive DNS errors, and others about local connection only, these errors will be fixed once your internet connection is resolved.


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## Green972 (Mar 8, 2013)

This is all so confusing, I apologize if I'm repeating myself or not understanding, it's a bit hard to understand there's so much going on.

So the modem was not receiving signals on that day of disconnection because of a faulty coax cable that need's to be repaired/replaced.



I don't know if it's possible for me to go outside with my entire desktop computer and see if the coax cable is giving connection. (and all houses in our neighbourhood are attached to one another) but it makes sense that I should have someone take a look at the cable.

So that's it, it's just the cable, nothing else is causing problems..

Q: Is the thing about internet being weighed down true? or no? repair guy said that to me once...and I'm sure he'll say it again.


Q: I just spoke to someone who said that modem's (and routers) have circuts etc. inside and sometimes they get fried or stop working, could something like that have happened to the modem?


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## alpenadiver (Jul 31, 2007)

Why not try the new modem? 
It could be the old modem, bad splitter, bad cable, or something down Rogers line.


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## AVB (Nov 28, 2014)

That coaxial cable is normally a RG6. You can temporary use a RG59 cable to test. The main problem with using RG59 is the attenuation level of the cable on long runs. Both the RG6 and RG59 are 75 ohm impedance. Note most TV coaxial cables are RG59 though RG6 are used for improve signal passage. Also your cable company would normally run a RG11 from their line to their exterior service box at your home.

Also those splitters used will lose about 3db (half the signal level just to split the signal). On top that every connector added will lose 1.5db or more so it desirable to have the least number connectors between the source and the receiver.


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