Cable modem for Charter

smokey982

SatelliteGuys Pro
Original poster
Sep 7, 2005
2,050
161
Cleveland, TN (Chattanooga Market)
I bought my own cable modem several years ago when I switched to Charter cable because at the time they were charging monthly rent to use theirs. So this morning I had a technician come out to move my modem from one room to another (my back won’t allow me to go under my house). Everything went smooth but as he was leaving I asked him about my speed. I’m supposed to be getting 100mbps in my area. And although I know my speeds are slower using WiFi. I’m only averaging between 20-30mbps. He told me it was because of my modem and that I needed to use theirs to get maximum speed. I’m currently using a Motorola Surfboard SB6120. According to the specs this modem should be good up to 150mbps. Is he correct about using their modem? Is there something about their modem that would allow faster speeds? I think he said they went away from Motorola a few years ago and now use Cisco.
If it matters I’m also using a Netgear N600 dual band router. Model number WNDR3400.
 
The 6120 is an ancient DOCSIS 3 modem from when DOCSIS 3 was a brand new technology in 2008/2009. It only bonds up to 4 channels downstream. You could get 150 Mb if you were the only one utilizing your node. From what I can tell Charter is pretty much standardized on 16 channels down, 4 channels up and a few areas have been 24 channels down for a while or will be upgraded to 24 in the not too distant future. Charter no longer charges a modem rental fee, so there is no reason not to use theirs. They will give you a modem that is inline with the infrastructure in your area. If they give you an all in one gateway, call up and have the modem put into bridge mode so you can continue to use your own router. If for whatever reason you want to buy your own, I think they have an approved modems list and I would get one that supports 24 channels down x either 4 or 8 channels up.

I would not accept a modem that uses the Intel Puma6 chipset

Do Not Buy List - Puma 6 Chipset
 
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Connect a computer directly to the modem via Ethernet and see what speed you get.

I was getting 105 with a SB6121 on Cox before upgrading my sisters modem with my SB6141 after I changed mine. They had 100/5 service at that time and now 150/10 which the 6141 does with no problems either.

Charter may be limiting speeds on the older modems or on non charter modems, however I bet it’s your router that’s the bottleneck, especially if you are on the 2.4Ghz channels.
 
I just ran some test.

Computer on WiFi 18mbps
Computer wired to router 19mbps

But for some reason when I connect the Ethernet cable directly to the modem I can’t get it to work at all. Is there a setting on the modem that needs to be changed?
 
As long as they no longer charge rent then I have no reason to buy my own modem. If they do give me an all in one. What advantage would I have using my own router?

There are lots of reasons people might want their own routers. The biggest one for me is that I don't want my router locked down by Charter. I want to have access to all the settings. If I need to setup port forwarding to make something work I want to be able to easily do that. When things like the KRACK vulnerability surface I want to be able to easily update the firmware. I want to be able to turn off security risks like WPS and UPnP.

Charter may not charge a modem fee anymore but they do charge a WiFi fee if you use their all-in-one without having the routing functions disabled. Using the same router you already have instead would allow you to remove that fee from your bill. A small side benefit is that you won't have to put the new network name and password into all of your devices.

Then there is the actual performance of the router. I bought a nice, dual band wireless AC router with gigabit ethernet ports. it also has guest network support so I can allow people to use my WiFi without giving them access to my entire network.

If you just want to get your devices on the internet and don't care about the WiFi fee their all-in-one is probably fine assuming it has enough range for your house. If you want control over your network and security you need to use your own router. If you want additional features or more speed and range you need your own router.

In summary, if you use their all-in-one you are probably getting a locked down, bargain bin router with a monthly fee.
 
I just ran some test.

Computer on WiFi 18mbps
Computer wired to router 19mbps

But for some reason when I connect the Ethernet cable directly to the modem I can’t get it to work at all. Is there a setting on the modem that needs to be changed?

You probably just need to unplug the modem and plug it back in to get it to assign an IP address to the computer. You will need to do the same when you plug your router back in.
 
I just ran some test.

Computer on WiFi 18mbps
Computer wired to router 19mbps

But for some reason when I connect the Ethernet cable directly to the modem I can’t get it to work at all. Is there a setting on the modem that needs to be changed?

Thanks. Unplugging the modem worked. But unfortunately I’m still only getting 19mbps plugged directly into the modem

The weird thing is when the test begins the speed starts out very fast. Around 90mbps plugged directly into modem and around 60mbps on WiFi. But as the test runs the speed slowly starts to drop.
 
Thanks. Unplugging the modem worked. But unfortunately I’m still only getting 19mbps plugged directly into the modem

The weird thing is when the test begins the speed starts out very fast. Around 90mbps plugged directly into modem and around 60mbps on WiFi. But as the test runs the speed slowly starts to drop.

If charter isn’t charging modem rental fees then I would just get a modem from them.
 
Thanks. Unplugging the modem worked. But unfortunately I’m still only getting 19mbps plugged directly into the modem

The weird thing is when the test begins the speed starts out very fast. Around 90mbps plugged directly into modem and around 60mbps on WiFi. But as the test runs the speed slowly starts to drop.

Sounds like either your modem isn't compatible with their current speed offerings or there is a problem with the internet in your area. I would start with a new modem since its free. If you have a local charter office in your area you should be able to just walk in and ask them for a modem that is compatible with the speed you pay for. If you don't want to pay their WiFi fee and use their router be sure to tell them because they try to sign you up for that by default.
 
In certain configurations, your modem will no doubt support up to 150 Mb/s but it would appear that the cablecos are using a different configuration and it won't reach that. With Time Warner and now Spectrum, a key factor is the # of downstream (and upstream) channels it supports. You need at least 16 x 4 channels - that will get you, I believe, up to 300/20 Mb/s speeds. I know for a fact, on Spectrum, it will get you 100+ / 10+ Mb/s. I have the SB6183, which is 16 x 4, and have the 100/10 speed plan and have no problem exceeding the advertised speeds.

Do you do online gaming ? If not, take whatever modem they give you. It will work and it's free.
 
I don’t do any gaming. And to be honest. I don’t really have any issues with the speed I’m actually getting. But if I’m paying for 100mbps, then I want to get 100mbps (or at least close to it). I’ll swing by the local office and see if they’re open today.
 
Good news! First speed test on the iPad with the new modem 92mbps. I’m a little surprised I’m getting that speed. The lady at Charter told me I’m still on the old $54.99 plan which they don’t offer anymore. She said to get 100mbps I would need to upgrade to the new $64.99 plan. I declined the upgrade for now. I wanted to see if the new modem made any difference without the upgrade. For some reason she couldn’t tell me what speed I should have with this old plan. She thought it was either 30 or 60mbps. But at 92mbps I think I’ll stay with my current plan. :)
 
Glad to hear your problem was solved by getting a new modem. On some modems if you go to the config page at http://192.168.100.1/ you can see the exact rate the modem is provisioned at. Charter over-provisions by roughly 20%. If you are the 60Mb plan you should max out at 72Mb, if on the 100 Mb plan you should see up to 118 Mb. I have Ultra 120 which is a temporary stopover until my area gets 300 Mb and I top out at 142 Mb. Upload is 10 Mb, I top out at 12. If you're getting 92 on wifi, you almost certainly have the 100 Mb plan

As long as they no longer charge rent then I have no reason to buy my own modem. If they do give me an all in one. What advantage would I have using my own router?

If on Standard you save $5/month. Charter charges $5/month if you use their wifi gateway, the charge is waved if you subscribe to Ultra.

If have my own Cisco wired router with a Cisco wireless access point for their advanced features that you won’t find on any cable company issued gateways and most standard home routers. I have site to site VPN tunnels between my router and the security appliances at my real job and my side gig for remote access. The router is dual WAN and I have it configured for failover with HughesNet, it also accepts USB cellular 3G/4G modems as failover but I live in a rural area with poor to nonexistent cell phone coverage from all providers. I also use custom access rules to prevent certain devices from accessing the WAN, but allow access to my LAN. And while most people would think of using content filtering, I’ve found that to be a little wonky so I also use access rules to block all social media (twitter, facebook and a few others) from being accessed on my network.
 
Good news! First speed test on the iPad with the new modem 92mbps. I’m a little surprised I’m getting that speed. The lady at Charter told me I’m still on the old $54.99 plan which they don’t offer anymore. She said to get 100mbps I would need to upgrade to the new $64.99 plan.
For some reason she couldn’t tell me what speed I should have with this old plan. She thought it was either 30 or 60mbps. But at 92mbps I think I’ll stay with my current plan.
My money says you are on the 100/10 plan. You just tested at a "bad" time and got a slight slowdown. Test again at various times and see what speeds you get. Also, just to be sure, though it's not mandatory, try a wired vs a wireless connection.
 
If the money is not an issue I would go and buy my own modem with Charter spectrum.

Depending on your situation I sometimes prefer the all in 1 modem router combo units which I have on my Charter account at my cabin.

I occasionally shut down the service in the winter. So it’s nice having to not to make a special trip to send the modem back