Problem with bringing internet to entertainment center

[Electric-T]

Ill start by saying im not sure if this question is in the right place.
That being said heres the situation....
Im bringing internet to a computer in my new entertainment room via ethernet. I have a main modem i think is distributing "raw" sigal from the box at the power line. On the output side, theres a coax cable that runs though the house to the tv boxes and modems. I realise now that i need a modem to decypher the singal for internet to be possible at the computer. This is after i ran 25 ft of ethernet haha.
So i have a few questions for you telecom guys/girls.
1. I do need a modem right?
2. Do all modems have coax input?
3. Do i have to use the coax input on the modem or are the ethernet ports bonded in such a way that i could use one as an input?

 

[Bluejets]

Do you have an ISP...internet service provider?
If so did they provide your modem?
Most countries, modems have wireless connection or otherwise cat5 for wired. (maybe even fibre)
Could be wrong but sounds to me like you are tapping into some form of tv distribution system.

 

[Electric-T]

Yes I have Spectrum. They installed the main modem and one for an existing computer. This is for a new computer. The main modem is fed by a phone line i believe. The output is a coax port. The coax goes throughout the house hitting every cable box and also goes to the existing modem.
There is am ethernet port on the main modem which i tried using to bring the signal to the new computer. I then found out that the signal was unreadable to the computer. So i must need a router. BUT i already ran ethernet from the main modem to the computer. I could easily get another modem but i want to use the existing wire i ran. I was just curious if there were modems that didnt need coax cables so i could use my wire and just run a short patch to the main. The more i talk....the more i think im answering my own question lol

 

[dave9]

TLDR: What is your modem make and model #?

Do you have DSL or cable internet?

What model of modem do you have, this will tell us even more than the answer to the above.

Either you have coax cable coming from your outside junction box to the modem input, if cable internet, -OR- you have a telephone line coming in from an outside junction box to the modem input if DSL. Do not confuse the modem's ethernet ports with telephone jacks if you are doing that.

Normally the modem will not have coax output. A Set Top Box might have coax output but will not have ethernet at all, and will not be a "modem" by name. Well, some of the newer generations for scrambled signals "might" have ethernet input but they are for TV signals, not really relevant to getting internet from a modem to a computer. Again knowing your modem model tells us a lot.

Most modern modems have their own routing with NAT and DHCP features in them and do not need a separate router, but will also work fine with a separate router, but again knowing what modem model you have will tremendously help.

In "most" cases, especially with ISP provided modems, if you had needed a separate router they would have provided one, but any modern modem does not need one. We could go into the security issues with not having a second layer of router, but that's a different topic.

A computer in a distant room should hook up to your modem the same was as one right next to it using an adjacent ethernet port. If you suspect you have a blown (damaged) ethernet port, try switching the ethernet cables around to see if a different one works. It is not uncommon for power surges to travel through network gear and blow a port out while the rest of the modem or router continues to work, or an unused port might accumulate dust or grime because being unused it is more exposed so once you go to try using it, the contacts need cleaned.

One thing is for sure, that you should not need a coax cable run from a modem to a distant computer to get it on the internet, unless you live in a time capsule and are using 10base-T which was coax cable based, and now is at least 20 years obsolete. I am pretty sure you aren't using 10base-T or you wouldn't have ethernet cable and sockets at all.

 

[Electric-T]

The modem is an Arris touchstone telephoney modem. After further research i think i know what happened here. The house had dsl to begin with. Then was later upgraded to cable internet and tv. They spliced into the phone line to feed the main router. The coax output distributes the signal throughout the house. Its picked up at every cable box and converted for cable tv. Its also feeding the modem at the computer. I think what i need to do is either run a piece of coax off of an existing splitter to a new modem or find a modem that can take an input via ethernet. This sounding right to anyone else? Im in the US by the way

 

[Electric-T]

Maybe something like this? Is the LAN port the signal input here? I think if i use a small ethernet cord from the main modems ethernet output to this i can use my existing run of ethernet to the computer. Problems with doing this?

 

[dave9]

WHAT MODEL MODEM? That is literally the only thing we needed to know and still do.

If I am understanding correctly, that you used to have DSL, but now do not have DSL, have only cable internet instead, then they did not splice into the phone line. They ran a coax cable to your premises, to a junction box on the outside, then a coax cable to your modem. There is no way to "splice into the phone line" to do this.

You might have some bizarro setup from Mars, but normally what you wrote is not at all correct. A cable internet modem has no coax output. It has a coax input, and ethernet output. You would have a splitter(s) on the coax line going to TVs, set top boxes, etc, anything that doesn't need the modem. All these things work independently of the modem and don't need it (except any telephone you have connected that only depends on the modem because it is now your phone system). That is an output from the modem to your phone wiring and we can ignore it for the purposes of what you're trying to do.

SO let's break it down into only the components you need to get the distant computer working. You have one computer working, plugged into the ethernet, yes?

All you need for an additional computer is to plug its ethernet cable into an adjacent LAN aka "ethernet" port. If you wanted to add a router, you would plug that into the WAN port.

To clarify I will bullet some points:

• You do not need to run any coax. Coax only distributes raw signal for video devices or a single modem. Since your single modem already has a coax connection, no further computing devices need it.
  
• You do not need a second modem, nor can you use a second modem unless you pay for a 2nd internet account. One modem is registered to each account.
• You do not need a modem that can take an input via ethernet to use cable internet.
  
• All you need is to plug a good ethernet cable into the appropriate lan/ethernet port on the back of your modem if it supports more than one lan/ethernet connection. If it does not support more than one, then you need at least a switch or probably a router.
• If you need a router, plug all ethernet connected systems into its lan ports, and plug its wan port into the modem.

 

[Bluejets]

I think someone's been hacking into an unknown area.
The modem in your last photo is dsl line in from the street with an outlet for a single phone, and the 4 ethernet ports for whatever pc.
Don't know what all this co-ax stuff is about or any LAN port INPUT.
Then again, we did away with DSL now that the NBN arrived and created it's own mass confusion.

 

[dave9]

IF you have a model TM1602 modem (manual linked below) then you only have one lan port on it as shown on page 18. In that case see page 30 of that manual. It states quote "I have two computer connected to the telephone modem, but only one can get on the internet. Check your cable company's terms of service: they may allow only one computer to connect directly to the telephony modem."

That suggests they have the ability to restrict to only a single device connection. For this reason, getting a router will solve that because it becomes that "one computer" in this context. The modem will only see the router as the only computer and then it is the router's job to connect everything else.

As mentioned previously you connect a router wan port to the modem's single ethernet port, then all computers to the router's lan ports.

Since the modem supports 1000Mb aka GbE (gigabit) ethernet, it would be wise to buy a router with a gigabit wan and lan ports. This will not bottleneck you to less than 100Mb throughput now or in the future.

https://www.timewarnercable.com/con...t/ModemUserGuides/arris-tm1602a-userguide.pdf

 

[Electric-T]

Thanks for all the replys. Im going to get in touch with Spectrum and see if i can even have another modem. I wanted to keep the computer on an ethernet connection. The coax is the input i see now. This clears it up. Thanks!