Warning: Do not buy a used cable modem.

There are several reasons why you would not buy a used or refurbished modem online.
But that does not mean in all cases. There are 2 exceptions where it is OK to buy a used or refurbished modem which we’ll cover below.

Why not to buy a used modem online

In the case of a used modem, a few buying options come to mind. You can buy a used modem pretty cheap on eBay or even on Amazon. But the risk that comes with the savings is not worth it.

First, let me state that I worked for Comcast Cable Internet for a long time and this knowledge is from direct experience as a technician and dispatcher for cable internet.

Every single modem has a unique identifier number tied to it. This is called the MAC Address. The MAC Address is on the actual modem, but it also must be added on the account it is associated with in order for the cable internet to be activated.

You can already see where this is going. If you buy a used modem, there is a high chance it is already associated with an account from the previous owner. This happens because it’s not something your average internet subscriber is aware of.

Without this knowledge, they just turn around and sell the modem. Or even donate it to Goodwill where the person you are buying it form obtains it to sell on Amazon or eBay.

What does this mean for you? When you buy a used modem, the cable company must put the MAC Address of the modem onto your account in order to activate it.

In the scenario where you bought it used from a random person, there is a very high chance that it will still be on the original account which is closed or abandoned. This means you are unable to activate your modem.

The customer service rep will not be able to help you or take your word for it that you have the modem. If this were the case you could pretty easily deactivate someone’s internet, even by mistake.

In some cases, they will allow you to bring the physical modem to the nearest brick and mortar store to verify you have the exact device you say you do. But this is a hassle and a time waste.

When is it OK to buy a used modem online

As mentioned it’s not all doom and gloom. You can buy a used modem from Craigslist, a friend or a Facebook Marketplace.

Why is this OK? You have the ability to talk to the seller, ask them or request that they call their cable company to have the modem removed from their account before you buy it.

If the modem is removed from all accounts then there is absolutely no problem with buying a used modem. If it works, it works. Period.

Buying a used modem could save you a few bucks.

Can I Buy A Refurbished Modem Online

This is where it gets tricky. I would not buy a “refurbished modem” on Amazon, eBay or any random website.

The only place you should buy a refurbished modem is direct from the manufacturer.

There are a few reasons. Unfortunately, the first reason is most sellers on these marketplaces will flat out lie to you. They will say it is refurbished or even new when they truly have no idea at all and can’t even test the equipment.

The actual modem test benches and laboratories required to certify a modem as refurbished are so expensive that only a select few including the manufacturer have access to them.

With 3rd party sellers, they generally just buy “return pallets” from major sources of defective returns. They then turn around and sell it 3rd party as new or refurbished. It’s a good gamble for them because oftentimes the modems will work for a month, 2, 3, or even 6. So they do not have to deal with returns or problems if they occur.

Another possibility is the modem comes with the wrong power cord which can be a fire hazard or cause damage to the modem itself by slowly overheating for a long period of time which will reduce the lifespan of the modem.

You also forfeit your warranty when buying from unauthorized sellers.

So the bottom line, if you have a trusted source and direct contact with the seller so that you may verify the modem is no longer attached to any accounts, you can buy the modem to save a few bucks.

If you are sure it is an authorized refurbishing facility, you may buy the modem.

We would just buy new to avoid any problems and you get the added benefit of securing a manufactures warranty.

Buying a New Modem Online

Comcast Xfinity
Refurbished Modem