Modems and Routers

By The Computer Guy

Date: March 23, 2019

     Do you have a modem? Do you have a router? Do you understand the difference between the two devices?  Allow me to explain. 

     The modem is your gateway to the internet. Without it you are not getting online. You could have the most expensive computer money can buy with all the cool bells and whistles, but if you have no modem, don’t expect to do any web surfing with that computer.  Modems are supplied by your ISP (Internet Service Provider), the most common being Comcast Xfinity, Charter Spectrum,  Verizon FIOS and DSL, and Fairpoint if you live in NH.  Internet access is delivered to your home or office through either a coax cable, or a phone line. Cable companies such as Charter and Comacast utilize coax cables as does Verizon's FIOS. A coax cable is a thick black round cable. It is the same type of cable used for cable TV.

     Phone lines are used for both dial up(remember the 90's) or DSL(Digital Subscriber Line) connections. Dial up is practically non existent these days, and DSL is heading that way. Verizon and Fairpoint are the two main suppliers of DSL connections.  Simply because of the much smaller size of the phone line as compared to a coax cable, internet speeds are very limited if you have DSL or god forbid, dial up. 

     So if you look at the outside of your home or business, you should be able to find either a phone line or a cable line(maybe both) running from your house or office to the nearest telephone pole. This is how the internet is delivered from your ISP to your home or office. However, a building doesn't know what to do with this incoming information. It needs something to decipher it all into usable information. Enter the modem. 

    Your modem will have either a coax cable or a phone line plugged into the back of it depending on what type of service you pay for. It will also have what is called an ethernet cable plugged into the back of it and the other end plugs into your computer.  It will take this incoming information being delivered to it and translate it into information that can be used by the computer. Without getting too technical,  this process of translating and delivering data is known as modulate and demodulate. If you look at the beginning of each word, MODulate/DEModulate, remove one D and you have MODEM. A little trivia tidbit for you to impress your friends with.  

      So you have your computer plugged into your modem via an Ethernet cable, and the modem plugged into either a coax cable or phone line. This is your direct line to the internet.  The world of email, Google, YouTube, Facebook and a host of other things are now at your fingertips. So if you have a modem to get you on the internet, what do you need a router for?   Good question and here is the answer. If you have only one computer in your home, you don’t need a router. You plug your computer directly into the modem, and you’re good to go. However, most people have  not only more than one computer in the house, but other devices needing internet access such as iPads, Kindles, PlayStations, Xboxes, and the lists goes on. In order to access the internet with multiple devices, a modem is not going to be enough. You will need a router also.  A router takes the internet signal supplied by the modem and splits it up for use by multiple devices.  Most routers have 5 Ethernet ports on them. Ethernet connections look like large phone jacks. One is marked as the WAN port. WAN stands for Wide Area Network, and for simplicities sake, let's just think of that as the internet. How do you connect to the internet? Through the modem. How do you get the router then to connect to the internet? By taking the ethernet cable plugged into the back of the modem and instead of running it to a computer, you run it to the router's WAN port. Now the router has access to the internet.  The other 4  ports are called the LAN ports. LAN stands for Local Area Network which would be all the devices in your house or office that you have connected to the router either wired, or wirelessly. Only 4 devices can be plugged directly into the router(sometimes more depending on the router, but 4 is the usual amount). So how do you connect more? This is where the joy of wireless comes in to play.  

    Wireless is like having an invisible wire running from your router to whichever device needs to be connected. People love using wireless because it gives them portability with their devices. This is extremely helpful with laptops, tablets, and phones. Wireless routers have a limited range. You can usually access your connection from within the house, and probably to some extent from outside, but the further you move away from the router, the weaker the connection becomes until finally it drops out completely.  A common question I get is why can my phone still connect when I'm miles from the house, or even in a different state or country than my house. That's because phones connect to the internet in two different ways. Their primary source of connecting is through cell phone towers set up all across the globe. This is how you connect when away from home and obviously any websurfing or email checking you do while away from home may add on to your cell phone bill. To reduce cost on the bill its better to connect to the internet through your router and modem when you're home. You will need to set the phone up to connect to your wireless the same way as you would for a laptop, tablet, or any other wireless device and once that's done you can surf away on your home network instead of on your cellular service. 

    Most routers come with what's called an encrypted wireless connection meaning you need to plug a password into the device you are trying to connect to the wireless signal generated by your router. This is an important security feature especially if you live in an apartment building or a neighborhood where the houses are fairly close to each other. Before encryption was standard on routers people would be broadcasting a wireless signal that anyone nearby could connect to. I had a client who unknowingly was supplying internet to half the apartment building. They called me because their internet was slow as molasses and when I checked their router I saw about 10 different people on it. They were getting their internet free through my client's open network. I must have infuriated a lot of tenants when I encrypted the network which shut them all out. Internet speeds for my customer increased dramatically and the freeloaders most likely had to order their own internet service after that.  Security may be a pain to deal with, but it is for your protection. 

    That's basically how modems and routers work together to get your devices onto the internet. If you have any questions feel free to contact me at