Modems. A modem is a device that connects a user to an ISP. Before there were ISPs, a modem made a data connection between two points. Modems are specific to the technology being used to make the connection.
In the picture accompanying this blog is an acoustic coupler, which is a modem that makes a data connection using the acoustic signals from an analog telephone. I used a 300 baud modem (which communicated at 300 bps – bits per second) around 1980 at Southwestern Bell when programming in basic. The modem allowed me to connect my telephone to a company mainframe modem and ‘type’ directly into programs stored on the mainframe.
Modems grew faster over time and by the 1990s we could communicate with a dial-up ISP. The first such modem I recalled using communicated at 28.8 kbps (28,800 bits per second). The technology was eventually upgraded to 56 kbps.
Around 2000, I upgraded to a 1 Mbps DSL modem from Verizon. This was a device that sat next to an existing telephone jack. If I recall, this first modem used ADSL technology. The type of DSL matters, because a customer upgrading to a different variety of DSL, such as VDSL2, has to swap to the appropriate modem.
In 2006 I was lucky enough to live in a neighborhood that was getting Verizon FiOS on fiber and I upgraded to 30 Mbps service. The modem for fiber is called an ONT (Optical Network Terminal) and was attached to the outside of my house. Verizon at the time was using BPON technology. A customer would have to swap ONTs to upgrade to newer fiber technologies like GPON.
Today I use broadband from Charter, delivered over a hybrid coaxial network. Cable modems use the DOCSIS standards developed by CableLabs. I have a 135 Mbps connection that is delivered using a DOCSIS 3.0 modem. If I want to upgrade to faster broadband, I’d have to swap to a DOCSIS 3.1 modem – the newest technology on the Charter network.
Routers. A router allows a broadband connection to be split to connect to multiple devices. Modern routers also contain other functions such as the ability to create a firewall or the ability to create a VPN connection.
The most common kind of router in homes is a WiFi router that can connect multiple devices to a single broadband connection. My first WiFi router came with my Verizon FiOS service. It was a single WiFi device intended to serve the whole home. Unfortunately, my house at the time was built in the 1940s and had plaster walls with metal lathing, which created a complete barrier to WiFi signals. Soon after I figured out the limitations on the WiFi I bought my first Ethernet router and used it to string broadband connections using cat 5 cables to other parts of the house. It’s probably good that I was single at the time because I had wires running all over the house!
Today it’s common for an ISP to combine the modem (which talks to the ISP network) and the router (which talks to the devices in the home) into a single device. I’ve always advised clients to not combine the modem and the WiFi router because if you want to upgrade only one of those two functions you have to replace the device. With separate devices, an ISP can upgrade just one function. That’s going to become an issue soon for many ISPs when customers start asking the ISPs to provide WiFi 6 modems.
Some ISPs go beyond a simple modem and router. For example, most Comcast broadband service to single-family homes provide a WiFi router for the home and a second WiFi router that broadcasts to nearby customers outside the home. These dual routers allow Comcast to claim to have millions of public WiFi hotspots. Many of my clients are now installing networked router systems for customers where multiple routers share the same network. These network systems can provide strong WiFi throughout a home, with the advantage that the same passwords are usable at each router.