Updated 2015.04.17
I developed this FAQ for a US Forum, but this question comes up a lot now that people are buying HDTVs with QAM tuners built in, or people wish to use Computer QAM cards.
In Canada, the answer is usually no, since most digital channels (including HD) are encrypted, save for the odd preview channel (or the channels you'd have anyway without paying extra). You therefore need to rent or buy a STB from the service provider or their authorized distributors to receive digital channels and you need to subscribe to the channels you want.
Occasionally you may also see VOD/PPV channels/movies that other people in your area are ordering. You will have no control over the movies, they may switch channels, they may pause/rewind, etc. I'm sure these channels will also soon be encrypted...
In the US (and a few smaller Canadian Cable companies) the answer is yes or no, depending.
You need to have a tuner that has "QAM" capability (this is the modulation used by most cable companies.)
You may then be able to pick up the unencrypted (unscrambled) digital cable stations. HD stations form some of this digital tier.
Most US cable companies do not encrypt the "local OTA-type" HD stations that they carry.
Most cable companies
do encrypt all other digital channels, including premium HD stations like HBO, ESPN, etc.
Sometimes, there may be digital channels that you may be able to receive, but they are usually the ones on "free preview".
This will vary from cable company to cable company and from location to location - see examples below.
Just because you can receive these now, you may not be able to receive them in the future.
In many cases, you simply need to connect the cable to the TV - you don't even need to subscribe to the digital tier, only analogue.
The channel numbers will likely not line up with the channel numbers used by the cable company, or TV guides.
There are some OTA STBs (ATSC/8VSB) that have QAM capability, but be careful and be aware of the limitations discussed above.
You can usually rent or purchase a STB from the cable company. The added features include such items as:
The ability to subscribe to any or all the digital channels
VOD (Video on Demand
PPV (Pay per view - via the remote)
IPG (Interactive programme guide)
SDV - necessary to tune some channels
PVR (this is an important one for many people - PVRs change the way you watch TV).
Future additional services.
Some TVs have a "CableCARD" option, which allows you to subscribe to all the channels, but doesn't provide the interactive services listed above with the STB. CableCARD is only available in the US, but even there is used by very few. Tru2Way was developed to address the lack of interactive services, however, it has gone nowhere.
Those people with
Rogers Ontario (GTA), may be interested in the following link which indicates the unencrypted channels:
http://www.remotecentral.com/hdtv/rogers.htm This can vary by location and has recently changed to almost no unencrypted TV channels, save an odd PPV, Free Preview, "Matrix/Mix/Interactive/6 picture channels" and the music channels.
Rogers Discussion:
http://www.digitalhome.ca/forum/showthread.php?t=153295
Other Canadian Service providers have been reported to have similar unencrypted channels.
Cogeco:
http://www.digitalhome.ca/forum/showthread.php?p=483945#post483945 (Cogeco, see posts 9, 12, 64 - differences probably due to different areas) Note that as of 2015, most of the channels in various areas appear to be encrypted. I'm amazed it took this long.
Mountain Cable:
http://www.digitalhome.ca/forum/showthread.php?p=525451#post525451
Shaw Cable:
Feedback indicates that most people seem to be able to get the music channels and not much else. There may be an occasional unencrypted channel, or one on free preview.
Eastlink
http://www.digitalhome.ca/forum/showthread.php?t=65917
Delta
http://www.digitalhome.ca/forum/showthread.php?t=63665
Persona
http://www.digitalhome.ca/forum/showthread.php?t=94197
If you have any comments or suggestions, please PM me.