# Controlling digital OTA boxes



## gastrof (Oct 31, 2003)

Anyone come up with a hack that will allow a Series 1 or 2 TiVo to emit the IR flashes needed to control channel changes on a digital OTA set top box?


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## classicsat (Feb 18, 2004)

I am thinking a microcontroller that pretends its a satellite or cable box, translating satellite/cable channel numbers to OTA channels (with a look-up table), and emulating the OTA box remote.


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## puffdaddy (Mar 1, 2006)

I'm pretty sure the OzTivo folks have done this.

To do this you would need to
a) learn the IR codes of the STB in question,
b) reverse the IR coding,
c) create new IR codes, encode into a slice, and load 

I tackled this by getting an old, activated voom receiver, told the tivo that I had an external DTV STB, and then set the IR code to General Instruments 10035.

Maybe others on the board can comment on whether or not they've found other Dish/DTV digital OTA receivers that don't require a sub to receive digital OTA. For such a box, we wouldn't need to remap the channels (although doing so is trivial), and then it would just be a matter of writing new IR codes if none of the current IR DB exists.


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## classicsat (Feb 18, 2004)

The real issue is dashed sub channels. The TiVo software in standalones don't know how to handle them.


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## puffdaddy (Mar 1, 2006)

Yea, though if there is only one subchannel of interest (typically the case for the major networks--if you don't care about silly weather maps) and if it's possible to cull out subchannels on the OTA receiver, then it will work without issue (e.g. a Voom box).


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## woodie (Feb 7, 2005)

I have created a couple tools that let me remap DIRECTV local channels to a digital OTA box.

http://www.netpress.com:3000/otasource.html

You need a nearby Linux box with 2 free serial ports, or a USB-to-serial adapter.

I will eventually write a DCT-2000 emulator, so I can get guide data for some of the PBS digital subchannels, but for now this works fine.


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## anonpost (Jan 5, 2008)

Some OTA digital tuners don't require a dash to tune to a subchannel. For example, my Sylvania SRZ3000 digital tuner interprets the remote control key sequence 0 6 2 as subchannel 6-2. I set RecieverNumDigits to 3 via dbset (see OzTivo site), so that my Series 1 Tivo always sends at least 3 digits to the digital tuner, by padding in front with zeros if needed. After I installed the SRZ3000 IR codes into my Tivo per the OzTivo IR How-Tos and set up my Tivo for satellite so it could control the SRZ3000, tuning my Series 1 Tivo to channel number 92 would transmit digits 0 9 2 to the SRZ3000 via the IR blaster and the SRZ3000 would tune to subchannel 9-2, while tuning the Tivo to 111 would transmit digits 1 1 1 and the SRZ3000 would tune to 11-1 which is main channel 11. Similarly, channel numbers such as 21, 72, 132, 201, 362 and 653 would tune to digital channels 2-1, 7-2, 13-2, 20-1, 36-2 and 65-3. However, tuning my Tivo to channel number 11 would cause the Tivo to transmit 0 1 1 which would be seen by the SRZ3000 as 1-1 (invalid), so a subscribed Tivo would have a problem accessing any main channel that had 2 digits; every main channel number needs to be referenced with the "1" suffix in order to accomodate the digital tuner. I have been using this subchannel numbering scheme for manual recordings since 2005. 

Changing channels with the Tivo is slow, about 5-8 seconds, so I mostly pre-record everything I watch; I no longer surf using the Tivo but sometimes surf thru digital channels using the digital tuner. I usually view a cropped picture on my 4:3 analog tv, though this can sometimes present a problem if text is cut off a 16:9 program (e.g. foreign subtitles).

The Zenith HDV420 digital tuner also works using this same/identical subchannel numbering scheme but set RecieverNumDigits to 4. I have second hand knowledge that the following OTA digital tuners probably work with this scheme: LG LST3100A and Hisense DB2010 (RecieverNumDigits 3). This scheme will not work with an RCA ATSC11 because the ATSC11 does not allow direct access to subchannels; you have to use channel up to access subchannels.

Alternate subchannel numbers: subchannel number 1302 may be used in place of a 3-digit subchannel such as 132, provided that your digital tuner will accept this as 13-02, i.e. an equivalent for 13-2. Another possible alternate is the subchannel number hidden by PSIP (as I recall, the Hisense DB2010 does not allow this type of access); but keep in mind that this number may change when analog is shutdown in 2009. I have had no problems using arbitrary subchannel numbers, except for one particular subchannel where I had to use an alternate because Tivo insisted on changing my subchannel number in its ToDo list to a different lower channel number that happened to have the same programming (possibly for uniqueness?). My Tivo is also set up for Antenna. Alternate subchannel numbers may also be useful when a NTSC analog TV channel happens to have the same number as a digital subchannel. 

I only needed serial BASH access to my Tivo to hack the IR codes; my Series 1 Tivo has no add-on network card. Of course the digital station names and the name of the satellite box used to control the digital tuner are not correctly displayed in the Tivo menus unless further hacking is done. In the Tivo Setup menu, I specified the satellite box with IR code 10001 with Medium speed and "enter key required" to control the digital tuner. After entering tivosh under BASH, I updated RecieverNumDigits and the SRZ3000 IR codes, used the "exit" command to return to BASH and then restarted my Tivo; I used dumpobj /Setup to see Source object numbers and dumpobj /Component/Ir/TivoFormat/10001 to show IR codes; replace CableBoxCodeNum 10001 with * to see a very long list of IR codes.

The two OzTivo IRConversion HowTos describe in detail how to convert Pronto IR format to Tivo IR format. Back in 2005, I used my JP1 remote to learn the SRZ3000 IR codes and then used these OzTivo descriptions to write a simple program to convert JP1 IR learned format to Tivo IR format. I could have done this by hand calculations but it would have been pretty tedious. Of course, you may be able to use the new OzTivo JP1 Capture HowTo if you possess the needed spreadsheet program. After installing the SRZ3000 IR codes into the Tivo, I used my JP1 remote control to re-learn the SRZ3000 IR codes transmitted by the Tivo IR blaster and then adjusted my conversion program so the converted Tivo IR codes were more accurate. Note that it appears the Makehex program on the JP1 site may be another way to generate Pronto IR format. I don't have a spreadsheet program, so I use JP1 RemoteMaster (RM) for customizing JP1 device upgrades; as I recall, the JP1 site had (at least partial) RM device upgrades for all the digital tuners mentioned in this post though possibly under a different model name. 

Have never tried this, but possibly a subscribed Series 1 Tivo could control the main channels of a digital tuner with RecieverNumDigits set to 1 or 2. However, the satellite setup would have to match the antenna channels/programming in your area and you would have to confirm that the digital tuner behaves correctly for main channel numbers entered without the suffix "-1". In addition subchannels (or an alternate) that did not require front padding with zero(s) might be manually recorded.


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## David_NC (May 1, 2008)

classicsat said:


> I am thinking a microcontroller that pretends its a satellite or cable box, translating satellite/cable channel numbers to OTA channels (with a look-up table), and emulating the OTA box remote.


I was thinking along the same lines. An external device that would plug into the IR blaster port or serial port (or have its own IR receiver), that would accept the channel changing commands and then translate and resend the commands to the converter box. 
Plug it into the serial port on your PC to program the station translation table and select the converter box model. 
The local cable system carries most of the local digital stations, so the guide data already exists.
Should be appealing to people who want to keep using the old series 1 Tivo's, but don't want to hack into them.


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