Digital and HDTV

[Terry]

Hi All:

1. Could someone explain to me why we are changing to HDTV?

2. Does HDTV use flybacks for picture lines and do they have "high voltage" for the screen? Radiation shields?

3. What if I am happy with my T.V. I have now?

4. I have Dish Network. Will I need another box or a different receiver? What if I don't want to change?

I would be interested in reading an article about HDTV if it is written in simple english.

Thanks;

Terry

 

[RJM62]

Re: Hdtv

Hi All:

1. Could someone explain to me why we are changing to HDTV?

2. Does HDTV use flybacks for picture lines and do they have "high voltage" for the screen? Radiation shields?

3. What if I am happy with my T.V. I have now?

4. I have Dish Network. Will I need another box or a different receiver? What if I don't want to change?

I would be interested in reading an article about HDTV if it is written in simple english.

Thanks;

Terry

1. HDTV offers better quality audio and video, wider aspect ratio, more efficient use of bandwidth, and more interactivity. Also, the present 700 MHz spectrum used by NTSC television is badly needed for digital telecommunications and will be auctioned off.

2. Yes, yes, and yes on CRT sets. (You must be an old TV repair guy! Not many people know what a flyback transformer is any more.)

3. You are basically out of luck. Well, not really. You can get an HDTV to NTSC converter. But you won't get the enhanced quality, and whether or not you get the interactive features depends on the unit you buy.

4. Probably, depending on how old it is. Dish Network has always used a digitized signal, but digital is not the same as HD. Satellite providers are not under the same requirements as over-the-air broadcasters, but over time, it's expected that most (if not all) non-HD programming will be discontinued. Satellite providers don't have unlimited bandwidth. As more HD channels are added, something else has to go.

5. http://electronics.howstuffworks.com/hdtv1.htm

Rich

 

[Terry]

Re: Hdtv

1. HDTV offers better quality audio and video, wider aspect ratio, more efficient use of bandwidth, and more interactivity. Also, the present 700 MHz spectrum used by NTSC television is badly needed for digital telecommunications and will be auctioned off.

2. Yes, yes, and yes on CRT sets. (You must be an old TV repair guy! Not many people know what a flyback transformer is any more.)

3. You are basically out of luck. Well, not really. You can get an HDTV to NTSC converter. But you won't get the enhanced quality, and whether or not you get the interactive features depends on the unit you buy.

4. Probably, depending on how old it is. Dish Network has always used a digitized signal, but digital is not the same as HD. Satellite providers are not under the same requirements as over-the-air broadcasters, but over time, it's expected that most (if not all) non-HD programming will be discontinued. Satellite providers don't have unlimited bandwidth. As more HD channels are added, something else has to go.

5. http://electronics.howstuffworks.com/hdtv1.htm

Rich

Rich:

Thanks for the answers.

Yes, I am old school, I mean "OLD" school. I built my own test equipment. Vacuum tube volt meter and a 3" RCA osciliscope. (SP?) Taught d.c. electricity in the Army, taught electronics at community college level. Then later worked as a Motorola t.v. repairman. (Ah the old days, sigh)

I built an audio amp that I could just touch the test lead anywhere in the circuit and with my BK test pattern generator could quickly troubleshoot by listening to the circuit over the speaker.

Thanks

Terry

 

[RJM62]

Re: Hdtv

Rich:

Thanks for the answers.

Yes, I am old school, I mean "OLD" school. I built my own test equipment. Vacuum tube volt meter and a 3" RCA osciliscope. (SP?) Taught d.c. electricity in the Army, taught electronics at community college level. Then later worked as a Motorola t.v. repairman. (Ah the old days, sigh)

I built an audio amp that I could just touch the test lead anywhere in the circuit and with my BK test pattern generator could quickly troubleshoot by listening to the circuit over the speaker.

Thanks

Terry

Wow, a kindred spirit!

I begged my father to buy me a cheap radio kit from Gem Electronics for my sixth birthday, and after I put it together (dad helped with the soldering; he had been a radio operator in the Army), the thing actually worked. And I was hooked.

I started building the usual electronics projects of the era: crystal radios, low-power radio transmitters, and so forth; as well as taking apart every electrical or electronic device in the house. My dad used to say that all I needed to be happy was anything with a wire attached to it.

When my next-door neighbor found out about my interest in electronics, he invited me up to his apartment. He was a retired TV repairman who still did some work on the side. I would sit on his lap or by his side as he showed me how to trace circuits, clean tuners, replace tubes, and discharge caps. We also took many a ride to Radio Shack and Gem Electronics with bags full of tubes to test, always stopping for an "egg cream" (which contained neither eggs nor cream) on the way back.

I spent my tenth birthday money on a used oscilloscope and a signal generator. By the time I was about 12, people in the neighborhood started dropping things off to be fixed or asking me to come over and look at their TV's.

I studied for my Radiotelephone license with the intention of going into Avionics, but somehow wound up in computers. This was when you actually had to have tools and know how to use them to fix computers. Now I'm looking to get out of it. It's just not much fun anymore. Ninety percent of the work is either malware removal or dumb user tricks. I do a little Web design, which is interesting mainly because I'm still pretty new at it; but I would still rather work on electronic hardware than sit at a keyboard.

I'm seriously considering selling out, taking some refresher courses, and going into avionics and/or marine radio repair.

Rich

 

[mikea]

Re: Hdtv

You won't have to change a thing as long as you pay for Dish or other TV system. What you won't be able to do once the digital-only switch is made is receive over the air.

BTW, it is DIGITAL TV that's coming, not necessarily HDTV, HDTV is a subset of Digital TV.

I predict that the analog TV shut down will be pushed back again. It certainly won't happen anywhere near an election year. There are going to be a lot of congresscritters getting angry calls from constituents asking how long they knew that TV was going to be turned off.

 

[RJM62]

Re: Hdtv

You won't have to change a thing as long as you pay for Dish or other TV system. What you won't be able to do once the digital-only switch is made is receive over the air.

BTW, it is DIGITAL TV that's coming, not necessarily HDTV, HDTV is a subset of Digital TV.

I predict that the analog TV shut down will be pushed back again. It certainly won't happen anywhere near an election year. There are going to be a lot of congresscritters getting angry calls from constituents asking how long they knew that TV was going to be turned off.

What do you mean by this, Mike? There will be and already are OTA HDTV channels. Do you mean he won't be able to receive OTA programming on his present television? I'm confuzled.

Also, I'm not sure what you mean by his not having to change a thing. All DishTV receivers are digital, but they're not all HDTV-capable.

Please explain.

Rich

 

[mikea]

Re: Hdtv

What do you mean by this, Mike? There will be and already are OTA HDTV channels. Do you mean he won't be able to receive OTA programming on his present television? I'm confuzled.

Yep. What I mean is that the old analog SD TVs will work as long as you have a box that outputs SD. The shock will come to those who use an antenna on the TV. Come switch day they'll get snow.

Also, I'm not sure what you mean by his not having to change a thing. All DishTV receivers are digital, but they're not all HDTV-capable.

Please explain.

Rich

DIGITAL over the air TV is what's coming. HDTV is carried on digital TV. So is standard def. Digital does not require HD. HD over-the-air does require a digital tuner. As I said, OTA HDTV is a subset of DTV.

What's changing
1) ANALOG (rabbit ears) TV will no longer be broadcast. This means standard televisions will need an external box to work.
2) DIGITAL TV is and will be broadcast.
3) Some DIGITAL is High Definition TV.
4) Most DIGITAL TV stations broadcast 4-6 multiple (HD or SD) channels.
http://www.avsforum.com/hdtvfaq/HDTV-FAQ.htm

If you're confused by that, imagine how many citizens are going be upset when the DTV-only-day comes.

 

[RJM62]

Re: Hdtv

Yep. What I mean is that the old analog SD TVs will work as long as you have a box that outputs SD. The shock will come to those who use an antenna on the TV. Come switch day they'll get snow.



DIGITAL over the air TV is what's coming. HDTV is carried on digital TV. So is standard def. Digital does not require HD. HD over-the-air does require a digital tuner. As I said, OTA HDTV is a subset of DTV.

What's changing
1) ANALOG (rabbit ears) TV will no longer be broadcast. This means standard televisions will need an external box to work.
2) DIGITAL TV is and will be broadcast.
3) Some DIGITAL is High Definition TV.
4) Most DIGITAL TV stations broadcast 4-6 multiple (HD or SD) channels.
http://www.avsforum.com/hdtvfaq/HDTV-FAQ.htm

If you're confused by that, imagine how many citizens are going be upset when the DTV-only-day comes.

No, we're on the same wavelength (pun intended ). When you said he wouldn't have to change a thing once the full change happens (whenever that may be), that's what threw me.

Thanks,

Rich

 

[mikea]

Re: Hdtv

No, we're on the same wavelength (pun intended ). When you said he wouldn't have to change a thing once the full change happens (whenever that may be), that's what threw me.

He won't have to change a thing as long as he uses a Dish receiver.

 

[Terry]

Re: Hdtv

Hi All:

My Mom has Cox cable. Is this digital? Will she need a box?

Terry

 

[KennyFlys]

Re: Hdtv

If it's anything like Charter, yes. A box is used to sort out the regular channels from the upper-end channels such as HBO, Showtime, etc. After that, more sorting for the HDTV channels. The box is controlled by the cable company's computer; no more filters at the distribution point off the trunk line.

 

[RJM62]

Re: Hdtv

I don't know about Cox Cable, but I'm under the impression they're all going digital little by little. (About two-thirds of Time-Warner's channels are digital at the moment.)

Rich

 

[mikea]

Re: Hdtv

Hi All:

My Mom has Cox cable. Is this digital? Will she need a box?

Terry

She probably has a cable receiver. Yes. You will need the receiver with an old TV.

 

[Steve]

Re: Hdtv

The primary reason for requiring commercial television broadcasters to switch to digital is the frequency spectrum currently used by analog television is being reassigned to emergency services.

http://www.spectrum.ieee.org/oct05/1911/3

 

[mikea]

Re: Hdtv

Hmmm. It didn't occur to me that the cable and satellite TV providers will have to convert OTA digital TV to analog for customers somewhere.
http://news.yahoo.com/s/ap/20070911/ap_on_hi_te/digital_cable;_ylt=A0WTcU0deuZGzHkA5gus0NUE
Could be fun to watch. I suspect that both will have to convert every local TV source facility. I'd bet we can leave to Comcast to make everybody get a digital receiver and charge for it, of course, no matter what the FCC wants.

 

[gismo]

Re: Hdtv

Hmmm. It didn't occur to me that the cable and satellite TV providers will have to convert OTA digital TV to analog for customers somewhere.
http://news.yahoo.com/s/ap/20070911/ap_on_hi_te/digital_cable;_ylt=A0WTcU0deuZGzHkA5gus0NUE
Could be fun to watch. I suspect that both will have to convert every local TV source facility. I'd bet we can leave to Comcast to make everybody get a digital receiver and charge for it, of course, no matter what the FCC wants.

AFaIK the receiver required for OTA digital TV is completely different than any set top boxes for digital cable. On the plus side, I expect that much of the next crop of digital TVs will allow for the insertion of a cable specific decoder card eliminating the need for another set top box if you use it with cable. Many of the current HDTV models already have this feature.

 

[wsuffa]

Re: Hdtv

Hi All:

1. Could someone explain to me why we are changing to HDTV?

Because the Government, in their infinite wisdom, have discovered that they can make a LOT of money by selling the spectrum that analog TV used to the highest bidder(s). The predecessor to selling highways, airspace, and ATC.

Digital quality and similar benefits are secondary. This is all about money.

2. Does HDTV use flybacks for picture lines and do they have "high voltage" for the screen? Radiation shields?

Yes, if you use a CRT display. No if you have a newer plasma, LED, LCD, DLP, etc. display.

3. What if I am happy with my T.V. I have now?

The government doesn't like you. Seriously, it is anticipated that someone will come out with a converter box, or you can subscribe to cable. Think of this as the government-mandated version of having to buy a new computer to use the latest version of Windows (except that the old versions stop working).

4. I have Dish Network. Will I need another box or a different receiver? What if I don't want to change?

For dish programming, no change. For over-the-air programming, you'll need a box or new receiver.

 

[mikea]

Re: Hdtv

AFaIK the receiver required for OTA digital TV is completely different than any set top boxes for digital cable. On the plus side, I expect that much of the next crop of digital TVs will allow for the insertion of a cable specific decoder card eliminating the need for another set top box if you use it with cable. Many of the current HDTV models already have this feature.

Right. OTA digital TV convertor/tuners are different from cable. What amazes me is that the few OTA DTV tuners are still $150-$200 right now - when you can buy an HD TiVo with that tuner built-in for $399. The guvmint is going to subsidize the cost of those BTW.

I predicted that you'd have Topaz brand tuners at Walgreens for $29 by now. No sign of that. There should be some conveniently at the $49 subsidy price at Radio Shack, Walgreens, Wal-Mart, Target etc. shortly after the screaming begins.

I say after because this drop dead date is now less than 18 months away and nobody is planning ahead. Gonna be fun to watch the hysteria during a election year. It just occurred to me. Local TV stations are going hemorrhage viewers. I wonder when they'll start banging the drum of warning.

What I was saying above is that pay TV suppliers have to have facilities to receive and forward local digital stations. I guess cable does that to some extent now to have locals in HD. The satellite guys would have to modify every local uplink - and have the bandwidth for locals in HD. That's why they're rushing new birds into service.

There's also gonna be a big demand for outdoor antenna installers. Might be a business I wanna get into.

 

[bjohnson]

Re: Hdtv

AFaIK the receiver required for OTA digital TV is completely different than any set top boxes for digital cable. On the plus side, I expect that much of the next crop of digital TVs will allow for the insertion of a cable specific decoder card eliminating the need for another set top box if you use it with cable. Many of the current HDTV models already have this feature.

Cable cards were available on many models 1-2 years ago. Now manufactures such as Sharp and Sony have eliminated that option due to lack of industry support. Sucks for customers that just want a stand alone TV.

 

[mikea]

Re: Hdtv

Cable cards were available on many models 1-2 years ago. Now manufactures such as Sharp and Sony have eliminated that option due to lack of industry support. Sucks for customers that just a stand alone TV.

The cable industry is fighting CableCARD tooth and nail. They're supposed to use them in their own boxes but just can't quit seem to get that working. The current cards are also one way only so you get no On demand or Pay per view.

There are so many halfway "solutions" these days that I'm tempted to just live with OTA antenna, online and DVDs for a while.

 

[gismo]

Re: Hdtv

The cable industry is fighting CableCARD tooth and nail. They're supposed to use them in their own boxes but just can't quit seem to get that working. The current cards are also one way only so you get no On demand or Pay per view.

There are so many halfway "solutions" these days that I'm tempted to just live with OTA antenna, online and DVDs for a while.

You'd think the cable companies would realize that TV compatibility is one of the big advantages they have over the dish. If I have to have a set top box for each analog TV in the house (and the HDTV I now have that gets locals off the air?) to receive digital cable, I'll probably just go with Satellite.

 

[mikea]

Re: Hdtv

You'd think the cable companies would realize that TV compatibility is one of the big advantages they have over the dish. If I have to have a set top box for each analog TV in the house (and the HDTV I now have that gets locals off the air?) to receive digital cable, I'll probably just go with Satellite.

It's another forward thinking industry. They want the extra $8-$12 a month they get for each box.

 

[mikea]

Re: Hdtv

You'd think the cable companies would realize that TV compatibility is one of the big advantages they have over the dish. If I have to have a set top box for each analog TV in the house (and the HDTV I now have that gets locals off the air?) to receive digital cable, I'll probably just go with Satellite.

It's another forward thinking industry. They want the extra $8-$12 a month they get for each box.

See?!

Cable operators argue that all they should be required to do is to carry the digital signal, as long as customers are informed that leasing a digital set-top box will bring in the must-carry stations.

http://www.hollywoodreporter.com/hr...sion/news/e3iff4aa14eba3699af918c7643da08f037

There's enough greed going around the move to new technologies that the U.S. is going to be among the last in no time.

 

[Kaye]

So out at the farm, we only get 2 channels. There is no cable (and I don't want a dish right now). Does this mean we'll have no TV?

 

[mikea]

So out at the farm, we only get 2 channels. There is no cable (and I don't want a dish right now). Does this mean we'll have no TV?

None after February 2009 unless you use your $50 federal subsidy to buy a digital tuner/convertor. Hopefully those will be priced at $50 or less by then.

Of course, you could use the $50 toward buying a new TV or TiVo with digital tuner, too.

 

[Kaye]

None after February 2009 unless you use your $50 federal subsidy to buy a digital tuner/convertor. Hopefully those will be priced at $50 or less by then.

Of course, you could use the $50 toward buying a new TV or TiVo with digital tuner, too.

And that would work out at the farm? We have tall hills around us, that's why we only get 2 channels now with an antenna.

 

[mikea]

And that would work out at the farm? We have tall hills around us, that's why we only get 2 channels now with an antenna.

It should work fine with the same antenna. You'll just get more channels and no ghosts or snow. You'll have to get used to that idea.

You might have to put up a bigger UHF antenna, but the odds are very good that if your antenna works now it'll work fine with digital TV.

Check at http://www.antennaweb.org to see what channels you'll get and the recommended antenna. If it says you need a fringe antenna for analog and the same class for digital, you'll have your verification.

 

[Kaye]

It should work fine with the same antenna. You'll just get more channels and no ghosts or snow. You'll have to get used to that idea.

You might have to put up a bigger UHF antenna, but the odds are very good that if your antenna works now it'll work fine with digital TV.

Check at http://www.antennaweb.org to see what channels you'll get and the recommended antenna. If it says you need a fringe antenna for analog and the same class for digtial, you'll have your verification.

But I don't want more channels! How will husband ever get the chores done if he's got more channels to click thru!

Thanks for the info!

 

[Ghery]

It should work fine with the same antenna. You'll just get more channels and no ghosts or snow. You'll have to get used to that idea.

You might have to put up a bigger UHF antenna, but the odds are very good that if your antenna works now it'll work fine with digital TV.

Check at http://www.antennaweb.org to see what channels you'll get and the recommended antenna. If it says you need a fringe antenna for analog and the same class for digtial, you'll have your verification.

Not necessarily just UHF. The VHF channels are not being vacated. Some stations will be broadcasting digital signals there. I tossed the paperwork a few days ago, but it's only the upper 10-15 channels that will be re-farmed. Of course, many upper channels were already re-farmed a number of years ago. Remember when there was a channel 83? Now the top will be somewhere around 60.

 

[mikea]

Not necessarily just UHF. The VHF channels are not being vacated. Some stations will be broadcasting digital signals there. I tossed the paperwork a few days ago, but it's only the upper 10-15 channels that will be re-farmed. Of course, many upper channels were already re-farmed a number of years ago. Remember when there was a channel 83? Now the top will be somewhere around 60.

Yeah. I shouldda said that. Currently all of the Chicago DTV channels are UHF, except channel 2 which of course had the last Super Bowl with Da Bears and has a lousy DTV signal that was unwatchable in the city.

I think I read that once the analog VHF channels are shut off, some VHF stations will move their currently UHF digital channels back to VHF. It's amazing there's a channel-to-frequency mapping mechanism to allow that to work.

 

[gismo]

And that would work out at the farm? We have tall hills around us, that's why we only get 2 channels now with an antenna.

How high is your antenna. IME with UHF (most digital is/will be UHF) you need at least enough height to have an unobstructed view for 10-20 miles or to the transmitting antenna. If there are deciduous trees in the way you are likely to lose signal in the summer, especially when the leaves are wet. And with digital, it's pretty much all or nothing. With analog a weak signal will give you a viewable but noisy (snowy) picture, but the same signal level means no picture at all with digital. A signal that's barely adequate for digital will give you intermittent reception. If you can get high enough you can probably get a decent digital signal as long as you get a big enough antenna. There are distance limits as well though even if you put the biggest antenna you can buy a hundred feet in the air you won't get a digital signal from 100 miles away AFaIK.

Personally, if I were a long distance from the transmitters, I'd definitely go with a dish.

 

[gismo]

Not necessarily just UHF. The VHF channels are not being vacated. Some stations will be broadcasting digital signals there. I tossed the paperwork a few days ago, but it's only the upper 10-15 channels that will be re-farmed. Of course, many upper channels were already re-farmed a number of years ago. Remember when there was a channel 83? Now the top will be somewhere around 60.

IIRC it's 69. And the UHF above that was take to pave the way for AMPS, the first (analog 800-900 Mhz) cellular service. BTW, it is/was technically possible to listen to analog cell traffic with your older TV set on the abandoned channels above 69, but it was also illegal. In fact it was actually illegal to own such a TV or any other receiver capable of picking up an analog cellular call.

 

[JimNtexas]

So out at the farm, we only get 2 channels. There is no cable (and I don't want a dish right now). Does this mean we'll have no TV?

The digital signals are often stronger and better than the analog signals. Many people find that they can use an indoor antenna for the digital broadcast channels, where they used to require an outdoor antenna for the analog channels.

You'll need either new TVs, cable or satellite service, or a set top converter box in 2009.

On the plus side you will probably get a better picture than you do now.

 

[wsuffa]

The digital signals are often stronger and better than the analog signals. Many people find that they can use an indoor antenna for the digital broadcast channels, where they used to require an outdoor antenna for the analog channels.

You'll need either new TVs, cable or satellite service, or a set top converter box in 2009.

On the plus side you will probably get a better picture than you do now.

Stronger? I don't think so. The DTV signals are of much lower power, sometimes as much as 1/1000 the power. When you can get them, they will be of better quality - they're either there or they're not. In San Antonio, they're much worse than the regular channels, signal wise.

DTV is also affected by multipath in a way that increases the BER so high that the signal is unusable.

 

[mikea]

Stronger? I don't think so. The DTV signals are of much lower power, sometimes as much as 1/1000 the power. When you can get them, they will be of better quality - they're either there or they're not. In San Antonio, they're much worse than the regular channels, signal wise.

DTV is also affected by multipath in a way that increases the BER so high that the signal is unusable.

DTV does have a failure mode that isn't snow or ghosting but is just as bad. You get a partial screen, stuttering audio, and the screen breaks up into huge pixel blocks like a mosaic. But hey, at least it's digital and it ain't ghosting.

Satellite TV and digital cable can do they same thing. The sad thing with pay TV is you get the overcompression artifacts and pixelation routinely when the system goes wonky and as they overcompress to fit in all of the shopping channels.

That's another benefit of of over the air broadcast digital TV. There are stricter standards on how many channels they can offer so (so far) the TV stations give you a high quality signal using all of the available bandwidth. So, ironically, these days cable TV, which was created to bring a better picture to customers will get smoked by customers that use an antenna instead.

 

[Ghery]

IIRC it's 69. And the UHF above that was take to pave the way for AMPS, the first (analog 800-900 Mhz) cellular service. BTW, it is/was technically possible to listen to analog cell traffic with your older TV set on the abandoned channels above 69, but it was also illegal. In fact it was actually illegal to own such a TV or any other receiver capable of picking up an analog cellular call.

Actually, I think it's just illegal to manufacture or sell a scanning receiver that can pick up the calls. Otherwise our EMC test equipment would be illegal.

FCC Rules, Section 15.2(v) defines a scanning receiver - "(v) Scanning receiver. For the purpose of this part, this is a receiver that automatically switches among two or more frequencies in the range of 30 to 960 MHz and that is capable of stopping at and receiving a radio signal detected on a frequency. Receivers designed solely for the reception of the broadcast signals under Part 73 of this chapter, for the reception of NOAA broadcast weather band signals, or for operation as part of a licensed service are not included in this definition."

FCC Rules, Section 15.121 deals further with the subject -

"(a) Except as provided in paragraph (c) of this section, scanning receivers and frequency converters designed or marketed for use with scanning receivers, shall:

(1) Be incapable of operating (tuning), or readily being altered by the user to operate, within the frequency bands allocated to the Cellular Radiotelephone Service in Part 22 of this chapter (cellular telephone bands). Scanning receivers capable of “readily being altered by the user” include, but are not limited to, those for which the ability to receive transmissions in the cellular telephone bands can be added by clipping the leads of, or installing, a simple component such as a diode, resistor or jumper wire; replacing a plug-in semiconductor chip; or programming a semiconductor chip using special access codes or an external device, such as a personal computer. Scanning receivers, and frequency converters designed for use with scanning receivers, also shall be incapable of converting digital cellular communication transmissions to analog voice audio.

(2) Be designed so that the tuning, control and filtering circuitry is inaccessible. The design must be such that any attempts to modify the equipment to receive transmissions from the Cellular Radiotelephone Service likely will render the receiver inoperable."

 

[gismo]

Actually, I think it's just illegal to manufacture or sell a scanning receiver that can pick up the calls. Otherwise our EMC test equipment would be illegal.

It may be state law, but I think there's a federal law that makes intercepting or owning a receiver capable of intercepting cellphone calls illegal. The FCC rules you quoted are indeed about the manufacture of a scanner that can receive the AMPS cellphone frequencies, but that's not what I was talking about.

Similarly, there have been laws making it illegal to own any device capable of generating audio signals that can mimic/defeat the old telephone system's inband signaling even though a whistle tuned to 2600 Hz or virtually any electric keyboard or organ is quite capable of doing exactly that.