Hackit: DTV Converter Boxes?


An anonymous Slashdot reader asked today what was the best digital television to analog converter box. He was looking for one with the best hacking potential. We actually purchased a Zenith DTT900 HD converter box this summer specifically wondering about the hacking potential. We did a teardown and you can find a full gallery on Flickr. Our conclusion was this: there’s not much there. You’re talking about a box that takes a digital RF signal and turns it into a crappier looking analog signal over composite. There isn’t much you can do outside of its designed use. Do you have any ideas what else can be done with it?

Slashdot commenter [timeOday] did mention a Tivax brand box that features a serial port. You can use it to issue remote commands to the box.

Not much has been said about the actual coupons. We’ve got a scan of them embedded below. The $40 coupons are essentially credit cards. We ran ours through a magstripe reader confirming this. Even though the card isn’t stamped with the recipient’s name, it is stored on the magstripe.


63 thoughts on “Hackit: DTV Converter Boxes?

  1. Has any popped the receiver open to see what is in there??
    You might be able to get some more info on the out put of that receiver and just by pass the LGDT1111D chip and just pipe that Video to your own converter system.

  2. i’m on my second government sponsored box made by apex, the first one burned out (smoke and everything) about half an hour after it was hooked up. i’m planning on buying a better one on my own dime, as for some reason whenever i’m on a channel that offers hd programs, it downscales too far and leaves a box around the entire picture. i have a 4:3 tv, and the image is 4:3, but it effectively takes about six inches off the picture.

  3. The Zenith DTT901 Digital TV Tuner Converter Box (also known as the Insignia NS-DXA1-APT) is pretty much the best rated converter box. You’d think that there wouldn’t be much difference but… some boxes have poorer image quality and other issues…

  4. Would it be possible to take the digital signal it receives and pipe it back out digital via HDMI or DVI? That would be a nice hack and allow me to watch TV on my monitor without a PC attached.

  5. The only possible thing I can even think of is making a TV antenna thing for the PC that goes over serial. Even then, without any type of custom system on it, you would have to make a program to run on the PC for it.

  6. The box I got from Radio Shack has a menu selection for Cable input (as opposed to Antenna). I hoped it would double as a QAM (digital cable) tuner but no such luck. I suspect that feature was disabled in the firmware or hardware but it might just be a jumper setting.

  7. For those not interested in a full-blown carputer, a converter box that runs on 12VDC could be installed in your car and hooked up to the AUX video input on a nav system or DVD player (for use by passengers or while stuck in traffic only, of course). Or maybe just use the guts to add DTV functionality to one of those portable LCD DVD players… You’d probably get a great signal in an airplane, though I’m not sure that’s one of the approved portable electronic devices for in-flight use.

  8. Hi everyone, not exactly on topic but I wasn’t sure where to put it. I was wondering if there was a way to build your own converter box. From the sound of the post, they are just converter rf to composite. If that is all, then could we just run up to radio shack and grab the parts and make it ourselves? I found this pdf with details on toshiba’s converter boxes and was wondering why it’s so complex looking? Perhaps it’s not the same thing? Anyway, just wondering if I could bypass all this pay for a converter box stuff and just make it myself.

    Any thoughts?


  9. I used to work in the STB industry… The biggest issues to hackability are:

    * Chip set used – how many on you know Transputer assembler used in the ST processors?
    * Accessability the JTAG – some have security fuse to disable port during manufacture

    Other than that they’re quite fun to play with. Transport stream from the demod will be un-encrypted but PS may be. GFX engines are quite powerfull with multiple planes and blitting.

    My favourite chipset set would probably be the Connexant range which are ARM9 based.

    Have fun,

  10. @ dokein, how would you get a better signal in a plane if all the digital tv is not going over the airwaves? That’s the whole reason for these fangled boxes. They’re getting rid of the old antenna method because too many people get their tv for free. bottom line is they want to MAKE you pay and to them that’s only fair after 50+ years of free viewing pleasure…


    errr, no, they are still sending free TV over the airwaves, it’s just digital, not analog. Old TV’s have always worked just fine, but after the cutoff, only new TV’s that can recieve digital TV will work, unless you have a converter box (hence this program). The signal still comes over the air, it’s just not compatible with old TV’s. It’s a nice signal too, looks better than HD cable or satellite (when going straight to a compatible HD tv, a converter box cuts the quality down).

  12. the earlier $40 card did have the name printed on it. I got 2 of them back when they were first issued, I never used them, I believe I still have it around however it has expired. I was unable to let my mother in law use it beauce of the name.

  13. All these converter boxes have incredibly crappy tuners. They cant receive anything. It’s like the LG LCD tv’s they cant receive any signals. My Panasonic 42″ plasma pulls in signals that all this other crap cant.

    If you want crappy, get these el-cheapo boxes. If you want good, go buy a $250.00 ATSC receiver.

    Oh and the $250.00 box has firewire, component, and lots of other stuff all you want to hack into these crummy boxes that cant receive a 30 mekawatt signal 1/4 mile away.

  14. Airplane would not work. 1) You’d pop in and out of signal range pretty quickly, and 2) You can’t demodulate the ATSC signal at all if your receiver is moving more than a few MPH. There are some mobile extensions being worked on[1], but they have little market penetration as yet. Same issues go for automobile applications, but it does lock on if you come to a stop or move slowly enough.

    -R C

    [1] Check google or wikipedia for ATSC-M/H

  15. Looks like you’ve got some flash, a ram and an everything BGA package chip. Otherwise, RF modulator with stereo capabilities, OTA receiver and switching power supply.

    No way that I see to get a digital stream of any sort out of it. You may be able to get a Y/C output, and then s-video it- but basically not real useful for hackers.

    As to the poster who thinks they can “run down to radio shack” and build one, you’re mistaken. See that big LG BGA mounted chip? It’s loaded with shit; decoding MPEG is not something you’re going to do with a PIC.

    What’s “digital RF” ? :-)

  16. @chrelad, the reason we need these boxes is specifically because the new digital over-the-air standard is not just analog rf in need of a demodulator. these signals are complex digital mpeg streams that must be demodulated, decoded, decompressed, and rendered. this is not something that can be done with any fixed logic or simple microcontrollers. and this is actually why we are interested: because a box fast enough to process digital tv might also be fast enough for other homebrew / hacked applications.

  17. If there’s some spare I/O available, how about hooking up a keyboard and SD card and turning it into a general purpose computer? Assuming boundary scan is not locked out, the flash can be written via JTAG.
    The OS wouldn’t have to be Linux – there are plenty of simpler alternatives, or how about no OS at all, just a basic interpreter or something? With all the CPU horsepower coupled to the fancy graphics it might make quite a nice system.

  18. Yeah, how’s this for a use: hack everything off it you don’t need and make a compact, portable DTV tuner for your LCD monitor, like the Sonic Impact V55. Bonus points if you can fit it all into an iPod-size box and actually dock it into that unit, run the video through an iPod connector, and even power it through the header. I’m taking a stab at this myself. Going to carve the AC/DC and RF out circuitry from the smallest unit I can find, to start.

  19. How about taking the guts and putting it inside an old VCR, then get the VCR to be able to power-up and change the channel on the converter’s tuner so it can do timed recordings, providing a cheap alternative to a DVR.

  20. how about using it as a receiver for wireless video broadcast in-house? if you could output your video through a NIC and receive it through the DTV box you could have wireless video streaming from your computer. sure, you would have to compress movies and such, but it is an idea.

  21. More DTV-vanilla than DTV-hacking related comment, but it seems the Consumer Reports review agrees on the Tivax brand being good among the cheapos. Anyone know a common store they’re usually stocked at?

  22. Look at the center-top of picture 05252008790 on your flicker.com. There is a spot for a connector, “CN400”. There are several traces on the circuit board that go from here directly to the CPU chip. This is probably for last-minute programming or for serial debug. Someone should take an oscilloscope and probe those pins, one at a time, during boot up and changing channels. If you see anything, it’s probably and indication of serial activity.

  23. I went down to circuit city today, and bought 2 Apex DTV converter boxes. They were on for about $47.00, So with the two converter box coupons, $14 for both! The box is rated middle road.. has analog pass thru.

    I might try to make a custom roof antenna for it, see how many channels I can get..

  24. Here’s a hack that I’d like to see – mod the box so it *always* passes analog RF, perhaps in tandem with disabling the RF modulator. That way you can daisy-chain a second CECB off the same antenna without resorting to using a splitter and you can operate both boxes simultaneously using each box’s composite video output.

  25. Let me start off by saying I don’t consider myself a “Newbie”, but I’m still learning. Not only this post, but all the posts that interest me give me information. Thank you to all of you who post and comment so I can learn from you.
    That being said, in MN area I have the hook up on turning those DTV credit cards into cash. I’m sure it could work elseware too. I’ll check back to see if anyone’s interested.

  26. I picked up to cheapo Magnavox stbs from wally-world. They picked up signals from the 2 closest cities (both about 25 miles away) with just a pair of rabbit ears. :)

    And SOOPERGOOMAN187 is the reason we have this government “sponsered” program…people are Stu-pid.

  27. I opened up the APEX-V100 from circuit city ($41). The PCB has 2 internal connector spots (ready to be soldered). One is for an RS-232 port. The other has 3 pins with labels JD2 and RD21 and RD23. Could this be for digital Audio out?

  28. Is there an way to get it to decode cable TV? I remember when I used to have Comcast I was able to connect the ‘Cable In’ cord into a VCr and I could flip through channels on the VCR and it acted as a free cable box when my mom didnt want to pay more money for a extra box lmao.

  29. Research the MPUs and find out how to init all the goodies (tuner, dacs, scalers, etc) and write your own custom TV tuner, perhaps throw up graphics and useful text with the OSD engine.

    Most of those MPUs have handy dandy Cpp toolkits. Shouldn’t be too hard to hack up a customized gadget from one of those coupon converters…

  30. Like Kweezxy157 asked, does anyone know if a DTV converter box will work with a cable TV signal?

    If so, they would be great for use with DVRs, DVD recorders, and PC capture cards that lack a digital tuner, without having to rent another cable box.

    My cable company, like probably all of them, sends both analog and digital channels (if you have digital cable), so I assume you’d want a converter box with analog signal pass-thru.

    Unfortunately, the Channel Master CM7000 (the only decent coupon-eligible converter with S-Video out) does not have analog signal pass-thru.

  31. I have the Channel Master D2A. Supposivly the BEST Box on the market with an S-Video Output. Love this thing. Great images and with the S-Video Output. Terk Indoor HD Antenna, I get 12 to 13 good channels four of the channels being HD. Only problem it converts HD into Analog just like any other box. Would have been purfect if they focused on the HDTV viewers instead of the m/fkrs who still have chathoid ray tubes. I wonder if there would be a software or hardware hack for this thing to Make the HD signal pass through as TRUE HD. Any Ideas?

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