HDTV vs HDTV Ready Using COmcast HD

[Lucas Tam]

"Mike" <wxyz09@yahoo.com> wrote in news:eYZHd.13279$Os6.2918@trnddc08:

> Is this correct? If I use a HDTV with enclosed HD tuner with Comcast HD
> signal which tuner do I use?

Does Comcast support CableCard? You would buy/rent a CableCard digital TV
tuner which you install inside your TV.

If Comcast doesn't support CableCard, you would have to use their external
tuner.

As for the built in HD Tuner - it's typically used for Over The Air
signals.

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[Stephen Neal]

"Mike" <wxyz09@yahoo.com> wrote in message
news:eYZHd.13279$Os6.2918@trnddc08...
> When using a HD Ready TV with Comcast HD signal I assume the HD tuner is
> supplied by Comcast.
> Is this correct? If I use a HDTV with enclosed HD tuner with Comcast HD
> signal which tuner do I use?

I prefix this by saying I'm a Brit. I also have a broadcast engineering
background and an interest in HD and Digital TV around the world.

AIUI Comcast is a digital cable provider in the US.

If you use their HD set-top box then the digital cable feed goes into this
box, which contains a tuner, decryption (possibly a hard drive if it is a
PVR model?), and MPEG2 decoding. It will then output an HD component
analogue, DVI or HDMI HD signal to feed to your TV. The Comcast box is
doing all the tuning - the HDTV is just acting as a monitor.

If your HDTV is digital cable ready, then it may have a "Cable Card" slot.
This means your TV will have a digital cable compatible tuner (most digital
cable is broadcast using a different modulation system to OTA HDTV in the
US - rather than OTA 8VSB it uses QAM modulation) into which you can connect
your digital cable feed without using a set top box. It will also contain an
MPEG2 decoder. However to allow for subscriber management, the decryption
system is not entirely provided as part of the TV. Instead a "CableCard"
module contains some specific decryption bits, so Comcast would have to
provide you with a CableCard to put into your CableCard slot.

So if you have a CableCard HDTV Digital Cable compatible TV AND Comcast
supply Cablecards then you may be able to use your HDTVs internal digital
cable tuner. If they don't supply a CableCard then you would have to use a
Comcast set-top box external tuner and connect it via component/DVI/HDMI
etc.

As I understand it the CableCard system hasn't been rolled out by every
digital cable provider in the US - I may be wrong but I think only a few are
supporting it as of now? There were all sorts of issues to do with programme
guide data compatibility etc.? From what I have read the use of external
tuners is far more widespread. (It also means it is possible to use a
cheaper HDTV as you can buy a receiver without any OTA HDTV tuner and MPEG2
decoding capabilities if you are purely going to source your HD digital
feeds from a cable set top box or a digital satellite receiver)

(There is also a possibility that your cable tuner box also has a Firewire
output. This will output MPEG2, for connection to a D-VHS machine for
recording, or for connection to a TV for display. If your TV accepts this
then your TV will also be MPEG2 decoding, though the cable box will still be
tuning and decrypting. Firewire MPEG2 input is only likely only if your TV
has an OTA HDTV tuner in it, as otherwise it is unlikely to contain an HDTV
MPEG2 decoder. AIUI Firewire input/output is not a "pure science" and the
industry doesn't favour it as it provides a nice source of uncompressed,
unencrypted HD... AIUI only some cable companies supply tuners/set-top
boxes with Firewire outputs that are enabled?)

Steve

[Mike]

When using a HD Ready TV with Comcast HD signal I assume the HD tuner is
supplied by Comcast.
Is this correct? If I use a HDTV with enclosed HD tuner with Comcast HD
signal which tuner do I use?

Thanks,

Mike

Some areas Comcast supports cablecards. Call your local office and Comcast
may be able to "hit" or "flash" your cablecard and activate your channels.
Also, when using the cablecard you don't get the channel guide and video on
demand stuff. Since I've got my Comcast dual tuner DVR box I've been hooked
and can't get to bed!

"Mike" <wxyz09@yahoo.com> wrote in message
news:eYZHd.13279$Os6.2918@trnddc08...
> When using a HD Ready TV with Comcast HD signal I assume the HD tuner is
> supplied by Comcast.
> Is this correct? If I use a HDTV with enclosed HD tuner with Comcast HD
> signal which tuner do I use?
>
> Thanks,
>
> Mike
>
>