Television Compatibility Information

The University of Mississippi digital cable system requires a television with a QAM tuner. You must check the specifications from your manufacturer to determine if it includes the required tuner.

QAM Tuner

QAM (quadrature amplitude modulation) is the format by which digital cable channels are encoded and transmitted via cable television providers, including The University of Mississippi. A QAM tuner is the cable equivalent of an ATSC tuner which receives over-the-air digital channels broadcast by local television stations. Many new cable-ready digital televisions support both of these standards. But, some very inexpensive manufacturers or models may not include the QAM tuner.

Digital Televisions

We have compiled the following information about television compatibility, and provide this list an informal reference for newer devices. This information is compiled from staff and student reports, and is not intended to be complete. The University of Mississippi cannot guarantee the accuracy of this information. You should verify the specifications before making a purchase.

It is important to be cautious of the televisions that are priced very cheaply, as manufacturers can save production expense by not equipping the television with a QAM tuner therefore allowing them to sell the television at a lower price. It is important to note that these are just general guidelines.

  • Dynex - Only limited models have a QAM tuner
  • Element - Only limited models have a QAM tuner
  • Emerson –Most models have a QAM tuner
  • HiSense - Do not appear to have QAM tuners
  • Hitachi - Most models have a QAM tuner
  • Insignia - Only limited models have a QAM tuner
  • LG - Most models since 2007 have a QAM tuner
  • Polaroid - Most models have a QAM tuner
  • Proscan - Do not appear to have QAM tuners
  • RCA - Do not appear to have QAM tuners, some do
  • Samsung - All models since 2009 have a QAM tuner (fifth digit of model number must be B or higher)
  • Sceptre - Do not appear to have QAM tuners.
  • Seiki - Only limited models have a QAM tuner
  • Sharp - Most models have a QAM tuner
  • Sony - Most models since 2007 have a QAM tuner
  • Sylvania - Do not appear to have QAM tuners
  • TCL - Most models have a QAM tuner
  • Toshiba - Most models since 2007 have a QAM tuner
  • Vizio - Recent models have a QAM tuner. Low cost Vizio models, appear to not have a tuner.
  • Westinghouse - Some models require QAM tuner activation

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Digital Conversion Boxes

If your television does not support a QAM tuner, you can update your television or purchase a digital conversion box. Just like the TV, you should ensure that the conversion boxes include a QAM tuner, and not just an ATSC tuner. Most tuner boxes available at electronic stores from over-the-air digital TV transition do not include this tuner, so be sure to verify the specifications from the manufacturer. The following boxes have been tested by the university for compatibility with our system. Please be advised that less expensive TVs sometimes come with a lower quality QAM tuner that may be unable to tune all of the channels. If that is the case a digital conversion box can be purchased.

Compatible Devices

  • ChannelMaster CM-7001
  • FireBird DCT210 (also available here)

Incompatible Devices

The following specific devices are equipped with a low-quality QAM tuner that is not capable of tuning the entire channel lineup. You may get limited or erratic service with these devices. The most common issue is the device freezing when tuned to one of the local broadcast channels over cable.

  • Access HD DTA1080
  • Digital Stream DTX9950
  • iView STB1000
  • iView STB2000

If you have any questions, please call the Telecommunications Center at 662-915-5922.

What’s the difference between QAM and ATSC?

Posted on September 14, 2012 by Doug Engstrom

The terms ATSC and QAM define how digital channels are broadcast. ATSC stands for Advanced Television Standards Committee and QAM is an acronym for Quadrature Amplitude Modulation.There is also QPSK, which is a format used for satellite broadcasting – but since those arereceived by proprietary satellite TV boxes, not HDTV tuners and TVs, it’s not important for this discussion.

Exciting, I know, but the terms have meaning.

QAM

QAM channels are designed to travel over wires, capable of supporting 38.4 Mpbs (megabits per second) of data, about 2 full HD programs or 7-12 SD programs. On a scope, it’s a very stable constellation of 64 or 256 points of data. By the way, the term is pronounced QAHM as in bomb, not QAAAM as in clam.

ATSC Channels

This type of channel, also known as 8-VSB, is broadcast over the air, received from an antenna to your TV orHDTV tuner. Looking at a the signal on a scope, the data points the carry the information appear a bit scattered compared to QAM, and it carries half the data, 19.2 Mbps. However, the standard works better in the air, where it has to bounce around obstacles and other types of interference.

In most cable systems, channels 2-13 are the same as off-air, then the rest of the channels are different. For some unknown reason, there are three types of channel spacing. Most use standard cable spacing, while IRC is the same except for channels 5 and 6, and HRC, where all the channel frequencies are different.

Tuning In

You can see that both are very different kinds of TV channels.Advanced HDTV tuners, such as the 232-ATSC+1 and HD TV sets can tune in both kinds of channels, and analog channels as well.Only a few tuners, such as the 232-ATSC+1, can accept both at the same time from a separate Air and Cable feeds.

Many low-cost TV tuners, such as the ones that convert HDTV to composite video, can only tune in ATSC. You need to check the specs to see if the tuner can handle QAM as well. Almost no low-cost tuners canreceiveanalog channels.

For most RF systems, you can’t mix ATSC and QAM channels over the same RF cable. The first reason is that, after channel 13, the frequencies are different. The second is that most TVs will skip any ATSC channels when scanning for cable, and skip QAM channels when scanning for off-air. Third, there are no commercial, affordable modulators that can broadcast ATSC channels over cable – the assumption is that all cable channels will be QAM.

The best way to mix in HD off-air programs with a cable system are to use special interfaces that can tune into an ATSC channel, then converts the program to a QAM channel for distribution.