eBay can be a great source of cellular phones and accessories. But there are some things you should know when shopping for them. Things you should consider before buying include provider compatibility, network technology, locked or unlocked, digital or analog, and usage times. There is also the question of whether to get a walkie-talkie phone. All of those things will be covered here.

Provider Compatibility

If you are going to buy a phone that is not unlocked, you need to know which provider the phone is programmed for. Preprogrammed phones will only work with the service provider they are set up for. For example, if you buy a phone that is set up for Bell, you cannot use it on the Telus network even though both networks use the same technology (and some of the same towers!) Sometimes a phone that is set to a specific provider can be unlocked (see Locked vs. Unlocked section below) but you are always safer buying a phone that you know is compatible.

Network Technology

This really comes into play when you are buying an unlocked (multi-network) phone, or if you don't have a phone currently and are trying to decide which network to go with. Knowing a little bit about each type of network can really help. Watch for sellers that advertise their unlocked phones as being compatible with "all networks"....for example, I have seen auctions advertising Bell, Telus, Solo, Rogers and Fido for one phone. This is impossible even with an unlocked phone because regardless of whether it's unlocked, a CDMA phone will not work on a GSM/GPRS network and vice versa. Make sure you know which technology the phone uses and use that information to determine network compatibility.

CDMA/EVDO: CDMA for voice, EVDO for date. These phones are currently the most common cellular technology in Canada. CDMA providers include Telus and Bell as well as Solo Mobile, which is a subsidiary of Bell. A CDMA phone will have excellent coverage in Canada and fairly good coverage in the United States, but will be almost useless when traveling anywhere else since most of the rest of the world uses GSM/GPRS. If you have more than one CDMA phone, you can switch between them but you have to call in each time. Also, you will need to manually transfer all your data from one phone to the other.

GSM/GPRS: GSM is the voice technology, and GPRS is the data technology. The major GSM/GPRS providers in Canada are Rogers and Fido. GSM/GPRS is a technology used worldwide and Canada's providers have roaming agreements with GSM/GPRS companies all over the world. This means that although it will cost more, you can use your GSM/GPRS phone almost anywhere you go. The main physical difference between CDMA and GSM/GPRS is the use of a SIM card. This in itself is a nice thing to have since with a SIM card, you can switch phones at any time without calling in. Simply put the SIM card into the phone you want to use and that phone will automatically be programmed with your phone number. GSM/GPRS providers are also introducing new technologies such as being able to point your phone at a vending machine and pay directly. These options are only available in Europe right now but North America is only a few years behind Europe with their GSM/GPRS technology.

Walkie-Talkie Phones: Currently Telus and Bell both offer this option. Telus has a separate network for their walkie-talkie phones (called Mike phones) and Bell's (called 10/4) work on their regular network. Bell has the advantage in this area because the Mike network is very limited and Mike phones don't work with Telus's regular towers.

Network Coverage: Each provider will try to tell you that their network is the stronger one for a variety of reasons. However, in reality, all the networks in Canada are nearly the same when it comes to coverage. Telus and Bell, although they are separate companies, actually use the same network of service towers so their coverage is absolutely identical. Rogers uses a different network because their technology is different, but their coverage area is the same size as Telus or Bell. Fido has a much smaller network, but since they are owned by Rogers, Fido customers can pay a small monthly fee to access the entire Rogers network. The only network that is at a significant disadvantage for coverage is the Telus Mike network, which doesn't work in the mountains or in many rural areas. Knowing this before choosing a provider can really help, since each provider will talk up their own network. Telus will tell you that they have better coverage than Bell, for example, when they actually use the exact same towers.

Locked vs. Unlocked

Why does it matter if your phone is unlocked if you have already chosen your cellular provider? If a phone is provider-branded, you are chained to that provider for as long as you use that phone. If another provider offers a better plan and you want to switch, you have to buy a new phone even if the network technology is the same. With an unlocked phone, you can use any provider that uses the same technology. For example, with an unlocked GSM/GPRS phone you can use Fido, Rogers, or any of the other GSM/GPRS providers around the world. This means that if you go overseas with an unlocked GSM/GPRS phone, you can take out your Rogers SIM card, put in a prepaid SIM card that you buy overseas, and by using a local provider you save huge $$ on roaming costs! There are a couple of different ways to unlock a phone and it helps to know about both. If you don't travel and you are happy with your current provider, it won't be a problem to buy a locked phone as long as you purchase one that's compatible.

Factory or OEM Unlocked: This means that the phone is programmed exactly as it was from the factory and has never been locked to a specific provider. This is the best kind of phone to buy because you know that every function of this phone will work with every available provider.

Carrier Unlocked: This means that the phone in question was at some point locked to a certain carrier, but has since been unlocked (usually using codes and specific software). These phones can be used with different providers, but higher functions (ie. text messaging and browsing) may still not work properly with all providers. When you are shopping, if the auction does not specify factory or OEM unlocked, ask the seller which company was the original provider.

Digital vs. Analog:

This only applies to CDMA phones. Some newer CDMA phones and most older ones can switch between digital and analog service (analog meaning that only voice calls will work). This extends your voice call service area because if there is no digital signal available, the phone will automatically switch to analog. When you are in analog mode your text messaging, browsing, etc. will not work but you can still place and receive calls. If you happen to buy a digital-only CDMA phone, you will not be able to use the phone at all in analog areas. A good way to decide: If you use your phone in any area where you sometimes drop calls or if you ever actually see your current phone go into analog mode, you probably should stick with a phone that has both analog and digital. UPDATED: In 2008, Telus and Bell made the switch to ALL DIGITAL networks. This means that any phone that is analog only WILL NOT work at all on these networks. Make sure if you are buying CDMA that the phone has digital, or both.

Usage Times

This can be important when buying a used phone. Most phones will have a call timer built in which shows the total minutes from all calls ever made on the phone. The higher this number is, the more the phone has been used. While the phone may still work perfectly (mine works great after three years of heavy use) keep in mind that large usage times can mean other things. These may include but are not limited to: scuff marks and scratches, marks on the screen, dead pixels in the screen, weak hinges, and broken antennas. These are all things that result from normal wear and tear but the call timer can give you an idea of what to expect. If you are buying a phone with high usage times, make sure that the seller show photos of the actual phone and close-ups of all screens so you know what you are getting. Also the auction should include a detailed description of the phone's condition, not just specs.