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Modems Wiring

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Cable Modems, Routers and DSL
Home Networking

Hookup to High-Speed Internet at Home
Cable Modems from Cable TV providers


Cable Modems

What is a modem?



A modem is an electronic device that allows your computers, smartphones, tablets, Smart TV and other devices to connect to the internet. The modem does this by converting digital signals from these devices into analog signals that can be transmitted over telephone lines or cable networks. Modems also do the opposite, converting incoming analog signals into digital signals so they can be processed by your devices.



What is the difference between a modem and a router? A modem is an electronic device that connects your home network to the world wide Internet via your service provider. A router is an electronic device that lets all of your wired and wireless devices use that Internet connection at once and also allows them to talk to one another without having to do so over the Internet.







Many homes have the coaxial cable from their cable TV/Internet service provider connecting them to the "headend" or cable company telecommunications facilities. The coaxial cable has greater capacity than the old phone company wires used for DSL.

The cable modem allows the home's digital devices to hook up to the coaxial cable.

How It Works

Cable modem service is offered through a partnership between the ISP (Internet Service Provider) and your local cable company. Typically, you'll be charged for broadband service on your cable bill, rather than paying the ISP directly. Your cable company is responsible for installing the cable modem and maintaining the quality of your service over the local cable network. At the main network office -- commonly referred to as the "headend" -- you're connected to the cable ISP's national backbone. It, in turn, is linked to the Internet.

If your cable modem service runs into a problem, you're best advised to call the cable company. A technican will probably be dispatched to your household if there's a cable network problem. If there's an ISP problem, the cable company will route your call to a technical support center to try to resolve the issue.




Cable Modem Hookup Diagram

Cable Modem Front Panel

1. power indicator - modem device is on

2. data receive

3. data send

4. Cable company connected link

5. User device link (PC or router)

Modem Light Indicators

Power Flashing – Startup diagnostics in progress.
Power On – Cable modem is powered on.

Receive Flashing – Scanning for a downstream channel.
Receive On – Downstream channel is connected.

Send Flashing – Scanning for an upstream channel.
Send On – Upstream channel is connected.

Online Flashing – Scanning for a network connection.
Online On – Startup process complete. Modem aqcuired.

Activity
Flashing or On – Transmitting or receiving data.

Standby
This light turns on when the standby button is pressed and standby mode is activated. If this light is on, all other lights will be off. Cuts off internet.

Cable Modem vs. DSL Comparison

When evaluating cable and DSL internet services, you should consider:

Speed: Cable boasts faster speed than DSL Internet in theory.

Popularity: In the U.S., cable Internet enjoys greater popularity than DSL. Outside the U.S., DSL continues to hold the edge.

Customer Satisfaction: In the U.S. cable services generally rate lower than DSL in customer surveys.

Security: Cable and DSL implement different network security. Historically, more concerns have existed with cable security. It's likely both DSL and cable are "secure enough" for most people's needs.

Cable modem Internet services on average promise higher levels of bandwidth than DSL Internet services, and this bandwidth roughly translates to raw speed. However, while cable Internet will theoretically run faster than DSL, several technical and business reasons can reduce or even eliminate this advantage.

In terms of theoretical peak performance, cable modem runs faster than DSL. Fiber Optic networks run faster than cable.

In practice, cable's speed advantage over DSL is much less than the theoretical numbers suggest. Cable modem services can slow down significantly if many people in your neighborhood access the Internet simultaenously. Both cable modem and DSL performance vary from one minute to the next depending on the pattern of use and traffic congestion on the Internet. DSL and cable Internet providers often implement so-called "speed caps" that limit the bandwidth of their services. Some home networks cannot match the speed of the Internet connection, lowering your performance.

Both cable and DSL service providers commonly employ bandwidth / speed caps for residential customers. Bandwidth caps place an artificial limit on the maximum speed a customer can achieve by monitoring their individual traffic flow and throttling network packets if necessary.

Service providers may have several motivations for imposing speed caps including the following:

o 1. Providers concerned about the capacity limits of their network may implement a cap so that they can accomodate more customers.
o 2. Providers may believe that the vast majority of customers do not actually need any more bandwidth than that allowed under the cap.
o 3. Providers may want to create a fair-and-equal distribution of bandwidth of customers. Without a cap, for example, some DSL subscribers would enjoy much higher bandwidth levels than others in the same neighborhood.
o 4. Providers may be want to charge higher or lower rates for greater or lesser bandwidth levels.

DSL - Digital Subscriber Line

ADSL (Asymmetric Digital Subscriber Line) is a form of Digital Subscriber Line (DSL) Internet service. ADSL provides greater bandwidth for downloads at the expense of upload speeds. ADSL is the most common form of DSL used in home networking.

ADSL is designed to support the typical home user who frequently downloads large amounts of data from Web sites but upload relatively less often. ADSL works by allocating a majority of the available phone line frequencies for communication of downstream traffic.

In other respects, ADSL possesses all of the characteristics one associates with DSL, including "high-speed" service, an "always on" combination of voice and data support, and availability and performance that is limited by physical distance. ADSL is technically capable of up to 6 Mbps (roughly 6000 Kbps), but ADSL customers in practice obtain 2 Mbps or lower for downloads and up to 512 Kbps for uploads.

VDSL

VDSL (Very-high-speed Digital Subscriber Line) was developed to support exceptionally high-bandwidth applications such as High-Definition Television (HDTV). VDSL is not as widely deployed as other forms of DSL service. However, VDSL can achieve data rates up to approximately 51,840 Kbps, making it the fastest available form of DSL.

To perform at this speed, VDSL relies on fiber optic cabling. VDSL is designed to work more as a business service that uses ATM internetworking rather than as a consumer service that utilizes IP. VDSL supports both voice and data communication on the same line, like other forms of DSL.

Also like most DSL technology, the performance of VDSL depends significantly on the physical distance traversed by wires: Shorter distances mean faster networking. The technology was originally named VADSL ('A' for asymmetric), but VDSL has now been improved and can operate in either symmetric and asymmetric modes.


CABLE MODEM

The cable modem connects to your computer with an (RJ-45) Ethernet connection (CAT-5 cable) or USB, and the coaxial jack (RF) on the cable modem connects to the cable company's line using a RG-6 type coax cable. You can hookup a router also so you can use multiple computers, even wireless such as a laptop.

Your TV can be connected also using a splitter and another coax cable hookup. The cable provider splits the TV signals and the internet data and routes to their destinations.

The cable modem has several lights on the front to indicate status.


DOCSIS 3.0 Data-over-Cable-Service


DOCSIS 3.0 Technology and Cable Operators

Cable operators across the U.S. provide high-speed Internet access to their customers through a broadband connection via a cable modem. These modems are based on DOCSIS technology, or Data Over Cable Service Interface Specifications.

DOCSIS has had four successive versions to date, each version providing improved broadband Internet connectivity, security features, quality, reliability, and flexibility. DOCSIS 3.0 makes it possible for cable operators to offer Internet connection speeds at hundreds of megabits and, potentially, hundreds of gigabits per second. DOCSIS 3.1 cable modems are available and are faster than 3.0 and DOCSIS 4.0 is looming on the horizon.

What is the Best Cable Modem?

Cable modem technology has come light years over the past decade. Utilizing DOCSIS 3.0 wideband technology, cable modems offer Internet download speeds of up to 50 to 300 Mbps with significantly faster speeds planned in the next few years. If you’re considering a new cable modem purchase, you’ll want to be sure that you’re purchasing top-of-the-line equipment that will give you access to the fastest connection speeds available.

Cable modems should offer fast and reliable Internet connections. To find out which modem will work best for you, it’s important to research the types of hardware products available and consider professional ratings and reviews for each.

You can find ratings of today’s top modems at SpeedGuide.net, an excellent resource for information about broadband and wideband Internet connections, cable modem and DSL technology, and TCP/IP performance over high speed/latency networks.

Another information website for cable modem research is ZDNet.com. Here you’ll find technical definitions, relevant articles, and product reviews for every type of cable modem available on the market today.

To ensure that any cable modem you purchase uses DOCSIS 3.0 wideband Internet capabilities, you can find a complete listing of approved manufacturers and devices at CableLabs.com. Cable Labs is the non-profit industry organization which developed DOCSIS technology. The organization also evaluates and certifies cable modems based on conformity to DOCSIS 3.0 standards. Products are tested based on fairness and verifiable criteria, rather than the opinions of testers or novice cable modem users. To find a complete list of Cable Labs certified products visit cablelabs.com/certqual/lists.

ARRIS/Motorola makes some very good cable modems.

Cable Modems and DOCSIS 3.1 Technology

If you’re buying a new cable modem, it’s paramount that your device includes DOCSIS 3.1 specifications to enable you to access the Internet at the fastest speeds currently available, and to be prepared for even faster speeds over the next few years.

DeviceMax download speed Max upload speedPrice rangeYear released
DOCSIS 3.0 1Gbps100Mbps$50-$1502006
DOCSIS 3.110Gbps2Gbps$150-$2502013


Buying a Cable Modem

When you get a cable modem, be sure it has the capabilities you need such as speed and compatibility with your service provider. If you need voice telephone service, be sure the modem has this capability as many do not. If you want to buy your own router, then the modem does not need a built-in router (Wi-Fi).

Check with your service provider to be sure you get a modem which will work with their network. They may have a recommended list of compatible modems such as the following:



Top 5 cable internet providers by availability

Xfinity (Comcast)
Spectrum (Charter)
Cox
Optimum
Astound

Top 5 fiber internet providers by availability

AT&T Fiber
Verizon Fios
Frontier Fiber
Quantum Fiber
Google Fiber

Cable Modem manufacturers

ARRIS/Motorola (Surfboard)
Netgear
Hitron


How to Configure TCP/IP

In addition to connecting your cable modem and computer, you will need to configure TCP/IP. On a windows PC, the procedure varies somewhat but generally follows the process of going into CONTROL PANEL, clicking on Network, clicking on LAN, selecting PROPERTIES, selecting Internet Protocol TCP/IP, select PROPERTIES and be sure to check the OBTAIN IP ADDRESS AUTOMATICALLY button. Also check OBTAIN DNS server address automatically. Next click OK. This will setup DHCP to get IP addresses automatically.

You can verify by the following process:
Windows computer - click START, then RUN and type in CMD (to enter command prompt mode). hit the enter key. A popup window should appear which allows you to type in IPCONFIG. hit enter key. You should see some results showing IP addresses. You can also type IPCONFIG/RENEW to renew IP address.

Your cable provider should help you configure your cable modem and assist with any problems.

GLOSSARY:

coaxial cable (coax) - A type of wire consisting of a center wire surrounded by insulation and a grounded shield of braided wire. The shield minimizes electrical and radio frequency interference. Home type coaxial cable is identified as RG-59 or RG-6 cable.

DOCSIS - The CableLabs Data-Over-Cable Service Interface Specification defines interface standards for cable modems and supporting equipment.

download - To copy a file from one computer to another. You can use the Internet to download files from a server to your home PC. A DOCSIS cable modem downloads its configuration from a server during start-up.

downstream - In a cable data network, downstream describes the direction of data received by your computer from the Internet.

Ethernet - The most widely used type of local area network (LAN). The most commonly installed Ethernet networks are called 10Base-T. 10Base-T provides transmission speeds up to 10 megabits per second (Mbps), usually over twisted-pair wire. Fast Ethernet (100Base-T) provides transmission speeds up to 100 Mbps.

expansion slot - An opening in a computer where a circuit board can be inserted to add new capabilities.

F-type connector - A connector used to connect coaxial cable to equipment.

IP address - An Internet Protocol address is an identifier for a computer or device on a TCP/IP network. Networks using the TCP/IP protocol route messages based on the destination IP address. Your cable service provider assigns your cable modem an IP address to provide a continuous Internet connection.

MAC address - The Media Access Control Address uniquely identifies each device that can be connected to an Ethernet network. It is permanently written to read-only memory (ROM) at the factory. You need to provide the MAC address to your cable service provider.

MHz Mega Hertz. A measure of radio frequency - millions of cycles per second. One MHz means one million cycles per second.

RJ-45 - The most common type of connector (jack) for Ethernet networks.

splitter - A splitter is a device that divides the signal power from an input cable equally between two or more signals, each carrying a selected frequency range.

TCP/IP - Transmission Control Protocol/Internet Protocol is a set of protocols that provides standards and rules for communication between networks.

Upstream - In a cable data network, upstream describes the direction of data sent from your computer to the Internet.

USB - Universal Serial Bus is a computer interface for add-on devices such as printers, scanners, and cable modems.

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