Not an expert. Rudimentary question.

Discussion in 'OT Technology' started by attomica, Jul 13, 2006.

  1. attomica

    attomica Active Member

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    How does cable work? I'm getting into a new house and will want cable TV in a couple rooms, cable internet in one room, and a security system tied into the cable as well. Can I split things up using a router or are there other devices? Will I need a cable tech to install a cable into each room for each purpose?

    Valuable assistance will be compensated for with my gratitude and good karma.
     
  2. 5Gen_Prelude

    5Gen_Prelude There might not be an "I" in the word "Team", but

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    You don't need any special hardware to split cable. Any cable splitter will do. Now you can go with powered splitters that reduce the signal loss if you want. If the drywall is already up, it's a little harder to run cable everywhere (although any builder will prerun cable).
     
  3. deusexaethera

    deusexaethera OT Supporter

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    The cable should have been strung up in multiple places throughout your house when it was first built. The trick is to only pay the Cable Guy to hook up ONE cable outlet because he charges you for each outlet he connects. Once he's connected a single outlet, then it's legal for you to connect all the rest yourself; all it takes to connect the cable is to screw the end of the cable into a splitter somewhere in your basement, garage, crawlspace, or in your side of the cable box on the end of your house. (you own half the box, the cable company owns the other half.)

    You may have to buy the splitter. If you're going to get cable internet, then you need to get a special kind of splitter:

    1. A passive splitter that sends a stronger signal through one output than through all the other outputs, so that you can connect your cable internet to the stronger output to get a more reliable internet connection, or...

    2. A TWO-WAY active splitter; normally, active splitters (which use a power supply to amplify each output signal) only allow the signal to pass in one direction, and this obviously will not work if you're going to use cable internet.

    Once you've gotten all the cable outlets in your house connected to an unholy combination of splitters, noise filters, and amplifiers, then you take the one special cable that has the strongest possible signal (no filters or other crap attached to it) and you hook up your cable modem to it.

    Your cable modem will decode the cable internet signal and send it to your router. Your router will either send out a bunch of Ethernet cables to your computers, or it will broadcast a wireless signal that your computers can tune in to. If you use a wireless signal, you will need to encode the signal so that people can't steal your bank account data when you pay your bills, and stuff like that. I'll let someone else explain how to encode a wireless signal, because my hands are getting tired.

    As for the rest of the cable outlets that you connected, well, you hook your TVs up to them. Remember; only ONE cable outlet gets used for your internet connection, and make sure it's got the strongest and least-interfered-with signal of all the cable outlets in your house.
     
  4. 5Gen_Prelude

    5Gen_Prelude There might not be an "I" in the word "Team", but

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    Cable internet doesn't require any special splitters. It's not a bad idea, but it's not necessary.
     
  5. deusexaethera

    deusexaethera OT Supporter

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    Yes, it does require special splitters, under certain conditions. If the cable in your house is older than a few years, it probably doesn't carry a good enough signal for you to be able to split the signal 4x or 6x and still have the cable modem able to decipher it.

    That's how it is in my parents' house, and they ended up needing a 3-way splitter that sent 75% of the original signal straight through to the cable modem, leaving the TVs to each use 12.5% of the original signal. TVs have built-in signal amplifiers, and cable modems don't because they would overheat if they had them.

    If we'd used a powered splitter, it would have had to be a special 2-way powered splitter, because the amplifier would have only allowed the signal to pass in one direction. 2-way powered splitters have an amplifier to split the incoming signal and a de-amplifier to combine all of the outgoing signals; regular powered splitters only have the amplifier, and they block outgoing signals altogether.
     
  6. P07r0457

    P07r0457 New Member

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    the misinformation is strong in this thread.

    But deusexaethera did post, so that is to be expected :rofl:


    would help if you gave more information, OP. Is this a new build or pre-built? What exactly do you want? What security system? etc?
     
  7. attomica

    attomica Active Member

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    Thanks to everyone for all the advice! I appreciate it immensely.

    What misinformation do you see, jollyogre?

    Answers:
    - This house was built in early 1980. Brick construction with a crawlspace.
    - I want a general understanding of how cable TV and internet lines works so I can grasp how to make all my stuff function. I'd like to make it so no cable techs have to come in to do stuff and collect fees.
    - It's a wireless, monitored security system with a main control panel, door sensors, motion detectors, siren, etc. We're not going to havbe a phone line, so to have it connected via broadband is the perfect solution.
     
  8. Ardentfrost

    Ardentfrost Jesus is so f*kin' metal

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    It's not hard to hook stuff up or even run cables and crimp RF ends. Setting up digital cable and/or internet is as easy as plugging the cable into a digital box. Everything runs on the same cable, every cable contains all digital and analog information, so just split it to wherever you need and hook it up.

    However, doing that does not necessarily mean that you will get good signal. If you don't want a tech to come to your house, you'll just have to hope lady luck is on your side. If after you connect everything up you have slow internet or digital cable that goes in and out, you will need a tech to come to your house. Tech's have special testing equipment that can look at the signal that comes into your house and at all locations around your house. They can find a bad termination, or tell you if you'll need to get a distrobution amplifier. There's no way around it unless you know someone who does tech work for the cable company, because those testers are quite expensive.
     
  9. deusexaethera

    deusexaethera OT Supporter

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    I guess I should have known better than to believe the cable guy who came to troubleshoot our internet connection. He only did it about five times a day, after all. :dunno:
     
  10. P07r0457

    P07r0457 New Member

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    I've met a few cable techs that knew what they were doing... but most are dumbasses that took a few day training course supplied by their contractor. They're there mostly to crimp cable, regurgitate standardized company-supplied responses, and plug in a diagnostics computer and let it do all the work.

    You can NOT just amplify a signal and have it be okay. If you amplify the root signal, you also amplify the noise (and introduce new noise) as well.

    As for the security system, do they support monitoring via broadband? Most require a local-loop. They do not use the same frequencies that voice communication uses, so they usually piggy-back the alarm circuit on an pre-existing voice circuit. However, if you do not have voice telephone service, they can still use a loop for the alarm circuit -- you just won't have dialtone.

    As for cable, RG6 is the way to go. Don't even waste time with RG59. Crimping connectors is VERY easy. Get some good high-quality F connectors. I got a free bag (had about 200 F connectors in it) from a Time Warner tech, once. Otherwise, go get some good connectors online from one of the wholesalers. Don't go to radioshack. Do NOT use twist-on connectors. Only use good crimp connectors. Get a good crimp tool. Ideal makes good crimpers, imho. I highly recommend a tool designed to strip RG6 cable. The one I have has two staggered spring-loaded blades of different depth. The shallow blade cuts the top jacket, while the deeper blade is staggered about 1/2" forward and cuts the inner insulation to reveal the center wire. Perfectly ready to insert into connector and crimp!

    What will you do for TVs and how many drops? You may or may not need a distribution panel for this. They make some really nice ones, depending on your needs. Complete with sealed enclosures, filters, amps, and power supply. Really need to plan that out, imo.

    Put the cable modem as close to the PoP as you can. Then run Cat6 to RJ45 keystones wherever you want ethernet access. The Cat6 runs should terminate at a patch panel in the MDF closet. For me, that's just a shelf in the garage. I have more Cat6 runs than I need, but that's because I do 2 runs per room, and where I knew I'd need it, I ran more. Then use short patch cables to connect the used patch ports to the switch/router.




    You can nigga-rig it and "plug-n-pray" but that's foolish, imo. If you plan it out, you can have a professional installation that far surpasses anything the cable tech would do...
     
  11. Ardentfrost

    Ardentfrost Jesus is so f*kin' metal

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    That's only true for analog amplifiers. An analog amplifier cannot tell the difference between the signal and the noise. However, digital amplifiers take the incoming signal and output a reconstructed signal. As long as the noise doesn't make 0's look like 1's, then it'll be cleaner when it comes out.

    Since digital signals degrade far sooner than analog signals, MOST modern problems with CATV cables come from the digital side of it. So, when the original poster starts doing stuff himself, if he runs into any problems it'll most likely be with his internet or digital cable (if he has that)
     
  12. P07r0457

    P07r0457 New Member

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    agreed. Cable modems are far more sensitive than a standard TV.
     
  13. deusexaethera

    deusexaethera OT Supporter

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    Dear god, I think you're agreeing with me:

    Anyway, Ardentfrost has a good point about digital signal amps. That said, a high-quality analog amp connected to a regulated power supply won't introduce any meaningful extra noise into the signal, and the cable modem is not going to be confused by the signal noise unless the amplifier boosts the noise MORE than it boosts the main signal -- that won't happen unless you use a really, really shitty amp.
     
  14. Ardentfrost

    Ardentfrost Jesus is so f*kin' metal

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    With analog amps, we're not talking about creating noise, but amplifying the existing noise. Noise occurs whenever the signal passes through a termination or runs near an electrical outlet or light or even from running a hair dryer on the same circuit as audio equipment. It's impossible to get rid of noise on an analog signal (which is one of the reasons I hated the electrical engineering classes I had to take). Once the original signal degrades to a certain point, no amount of amplification will salvage it because the signal to noise ratio does not change when amplified.
     
  15. 5Gen_Prelude

    5Gen_Prelude There might not be an "I" in the word "Team", but

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    Well, all I can tell you is what I've experienced. I've setup cable in my 20 year old apartment, my 1 year old condo, my brother's 80 year old house and my mum's 10 year old condo. I've run bandwidth tests without anything else plugged into the outlet, everything plugged in, and everything plugged in drawing signal. Regardless of using various splitters and amplifiers, it made little or no difference to the quality of internet connection, digital tv, and/or analog tv - especially when common sense was used and the digital signals were not split more than once.

    Regardless of which route you go down, your wiring concerns remain the same. If you find that you are running into interference, you can then make the efforts to rectify them after the fact.

    As a sidebar, I have resolved many of these interference problems by looking at how the runs are made (ie outside sources interfering with the cable).

    I don't disagree with the "right answer", I just think you need to take it with a grain of salt. 10BaseT works perfectly well punched down 1-8 (which if you look at it means you are splitting a pair). Is it right? No. Does it work? Yes.
     
  16. attomica

    attomica Active Member

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    Again, thanks to all for your advice. I'll print this all out and have it ready for when we close at the end of the month.

    Yes. That is actually the reason I am targeting this system because I don't want an active phone line. We use our cell phones for outside communication. The system is wireless, which I'm assuming means the control unit is connected to the cable for monitoring and all the sensors have a wireless link to the control unit. I'm just unclear on how the controller will interface with the cable.

    I will have a TV in the living room, kitchen and master suite. There is already cable in the living room and the kitchen, but there are none in the master suite or the office, where I'll need internet.

    Please define PoP.

    My objective is to bring cable service into the rooms that don't have it yet without paying for a tech to come out and do it. I didn't know anything about signal degradation, so I'll keep that in mind when running my equipment.

    Any other thoughts will definitely be appreciated.
     
  17. Ardentfrost

    Ardentfrost Jesus is so f*kin' metal

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    PoP is Point of Presence... he's talking about where the cable comes into your house. But a wire with clean terminations going through as few splitters as possible should be fine no matter the drop length (within reason).

    I suggest testing lengths and drop locations before running cables in walls. That way you know if you're going to have problems before you start drilling any holes or pushing wire through insulation or anything.
     
  18. deusexaethera

    deusexaethera OT Supporter

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    I know you're talking about amplifying the existing noise. What I was trying to say (though I said it fairly clumsily) is that the cable modem will only interpret the noise as data if the signal-to-noise ratio exceeds a certain amount. That means that, if the original SNR is 10:1, all the analog amplifier has to do is maintain the signal at 10x the loudness of the noise and the cable modem will interpret it the exact same way it would have interpreted a non-amplified signal. Meanwhile, because the signal has been amplified, it can be split more times before it becomes too quiet for the cable modem to interpret.
     
  19. P07r0457

    P07r0457 New Member

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    you want a gate digital amp... It's way more complicated than a simple amp... that's the only amp i'd use.
     
  20. Ardentfrost

    Ardentfrost Jesus is so f*kin' metal

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    cable modem = digital
    analog amplifier = amplifies analog signal with its noise
    analog amplifier != amplifies digital signal
    digital amplifier != amplifies noise
    digital amplifier = reconstructs digital signal
    SNR has little to do with a digital signal unless it's an ADC

    it seems the concepts of analog and digital signals, their amplification, and signal degradation is eluding you, because you're interchanging the concepts :dunno:
     
  21. deusexaethera

    deusexaethera OT Supporter

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    And it seems that you don't realize that a digital signal is just an analog waveform that is interpreted using a single threshold instead of multiple thresholds: either the peak voltage is above the threshold and it's interpreted as a 1, or it's below the threshold and it's interpreted as a 0. There is no such thing as a "digital signal"; the part of the process that makes it digital is the modulation scheme at the source and the demodulation scheme at the destination. When the signal is traveling down the cable, it's a sinewave just like any other signal is.

    You are right that a digital amplifier reduces noise by interpreting the incoming signal and completely reconstructing a new, identical outgoing signal. That said, a good analog amplifier will not cause the existing noise to be stronger relative to the intended signal, and as such the analog-amplified signal will not suffer any degradation that would result in changing 0's to 1's and vice versa. Not to mention that the analog amplifier will cost a lot less because it won't need to have sophisticated electronics to interpret and reconstruct the original signal.
     
  22. Ardentfrost

    Ardentfrost Jesus is so f*kin' metal

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    we've moved far away from the poster's concerns, so I"ll just say that for CATV, depending on the amplifier you get will depend on what frequency bands it amplifies. Therefore, no, an analog amplifier would not be amplifying the digital signal contained within the cable. If it did, it could damage digital equipment that might be expecting a 1 to be 1 Volt, but receives something a lot higher. Amplifiers can be digital/analog, digital, or analog. Additionally, not that it matters, but digital amplifiers must also amplify in both directions whereas analog amps don't need to.
     
  23. deusexaethera

    deusexaethera OT Supporter

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    I agree that we've gotten off the topic. But, since the OP already thanked us for the help and moved on with his life, I figure a little academic debate is good clean fun.

    It sounds like you're referring to amplifiers with frequency filters built in. As you implied, analog cable and digital cable operate on different frequencies, and cable internet operates on a yet a third frequency band, so certain amplifiers may be tuned to filter out frequencies that they aren't "supposed" to amplify.

    I was referring to an analog amplifier as a simple transistor that exactly reproduces whatever input signal it receives (regardless of amplitude or frequency), whereas a digital amplifier uses a gated transistor that only allows a signal to pass when the signal's amplitude exceeds n volts (where n volts is the definition of a binary 1), thus eliminating any noise lurking in the background.

    :dunno:
     
  24. Ardentfrost

    Ardentfrost Jesus is so f*kin' metal

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    CATV isn't as simple as just amplifying whatever is there. It used to be, but notsomuch anymore when you have digital coming to your house. Internet = digital, so that CAN add complications to what the OP was needing. That's why I originally suggested that they give it a try, but if it doesn't work, to call the tech, because they will be able to tell exactly what is wrong and/or needed better than we can suggest by reading a lmited amount of information on the internet ;)
     

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