You may think you only need an extender when you have a complicated home theater setup, or if you are running out of keymove macro space.  I hope from this example you can see how even a simple setup can benefit from an extender. 

Figure 1

Figure 1 shows my guest room/den setup before my cable company announced they were going all digital.  I basically needed a remote that was either the DVD/VCR or the digital TV.  My TV was receiving my complete cable package and even a few digital channels. 

Then my cable company changed to require a set top box for basic cable.  I was issued a simple DTA box for my basic cable system.  This box itself had RF in and out connections but there were no buttons on the unit itself. 

The remote was a universal remote that controlled the TV’s volume and power functions.  The rest of the buttons controlled the DTA functions.

A simple volume punch through and keymove to a power button could simulate this remote no problem.  However it starts to get confusing if you are using a remote that doesn’t have native channel punch through.

The DTA box tunes in channels converts the selected channel to an analog RF signal that it sends out on channel 3 or 4. 

My first question was, do I NEED to convert everything to analog, since I have a digital TV.  The answer was I could get some local channels without the box, but I needed a DTA to get my basic cable channels, or a HD Set Top box at an extra $ charge if I wanted HD service for my digital TV. 

Figure 2

I plugged my equipment in as shown in figure 2.  I executed the TV’s scan, and my TV only found channel 3, none of the digital channels made it through the DTA box.  So all those brilliant HD channels that made the TV so appealing were gone now that the cable company had going all digital. 

When I tried to use my TV’s remote to do some of the features I use, like changing the picture quality, turning on closed captions, or changing the sound to surround sound, the DTA kept changing channels.   I called my cable provider, trying to get this issue resolved by changing to a different DTA box, or perhaps a firmware download, but none of the people that I talked to had any solution for me.  Fortunately the upgrade that I made with the JP1 tools sent the Sharp TV signals at a slightly different frequency, and that cleared up the interference issues I was having with the DTA without my having to make adjustments to the protocol myself.   Now I could use some of the advanced features on my TV without having the DTA constantly changing channels, but I was still unhappy because I didn’t have any HD for my HD TV.  I removed the DTA box did a channel scan to see if there were still HD channels available now that the digital conversion was complete.  The local HD channels were available but most of the “cable only” channels were missing from the lineup juar as the cable rep told me they would be. 

So I decided to see if I could get my local HD channels and my cable by using a splitter.

Figure 3


With the setup in figure 3, the DVD/VCR setup needs to be turned on to watch the TV, because the cable is getting passed through AV inputs.  The TV is set to tune in just the HD channels, the rest of the channels have been skipped or removed from the TV’s list for use with channel up and down.

I’ve also done my due diligence.   The TV has discrete on/off and all the input discretes except the TV tuner.  The TV ch+ or ch- key will force the TV Tuner even though there is no discrete. The DVD/VCR has no discretes, although opening and closing the DVD will force the unit to turn on.  I decided it is not acceptable to me to use the open/close as a discrete on hack, as this seems like undo wear and tear on the unit.  So it is going to be a toggling setup.

Now that I’ve got the wiring done, and the stations edited, the reality of how complex this is to operate with a remote becomes apparent, even though I’ve done the wiring myself, half the time I can’t figure out what mode the remote is in.  Since this remote is in the guest room/den/office it needs to be simple to use. 


I’ve chosen a Comcast 3 device remote for this application.

Ideally this remote would use its ‘ALL ON’ button to turn on the equipment and prepare for watching cable. 

To view cable from the DTA box, the DVD/VCR needs to be on and  tuned in to channel 03; the TV source needs to be AV inputs; and the channel buttons are set to the DTA while the menu and volume buttons are pointing to the TV.

This of course is easy with an extender installed and enabled.



In an unextended remote,  pressing a device button sets a device index.  When an extender is in use, the device keys do not do anything unless there is a macro or keymove associated with them.

Most extenders do some sort of home theater selection, this is usually  accomplished by putting a macro on the device buttons

This extender has divided the keys into P_C_V_T_ O_ and X_ settings.  Each group can be assigned an independent device index.   

The first thing to look at in the IR file are the device selection macros on the Aux, TV and CBL buttons. 

Figure 4 Key Divisions

Below are the macros used to tame this setup.

# Target Key Macro Keys
1 CABLE  V_TV; T_AUX; O_TV;   P_TV; C_CBL;X_CBL;Phantom1
2 TV  V_TV; T_AUX; O_TV;   P_TV; C_TV; X_TV;Phantom1 
3 AUX  V_TV; T_AUX; O_AUX; P_AUX; C_AUX;X_AUX;Phantom1
4 All_On X_AUX;Power;X_TV;Power;TV; X_AUX;3;X_TV;PIP_Swap;CABLE

So when we press the Cable

V_TV; sets the volume  buttons to the TV
T_AUX; sets the transport buttons to the Aux-DVD/VCR
O_TV; set the device buttons and the menu buttons to the TV controls
P_TV; sets the picture-in-picture to  the TV controls
C_CBL; sets the channel control buttons to the cable controls 
X_CBL; temporarily sets ALL the keys to the cable controls until the macro ends or a x_cancel is encountered.
Phantom1  does whatever is stored on the cbl/phantom1 key, in this case its an input selection sequence if the key is held down

Now the key associations could be accomplished with keymoves, but is easier, cleaner and more versatile using home theater settings.  There are some other features in use too.


1     CABLE/Phantom1 LKP(2)

[Short]:< Blank >  [Long]:X_TV;PIP_Swap;X_Cancel
Change  TV to AV Input

2 TV/Phantom1 LKP(2)

[Short]:< Blank >  [Long]:X_TV;Ch+;X_Cancel  

Change  TV to RF input. 

Note the Ch+ and Ch- function as discretes, but if you are already in tuner mode, they will change the channel.   

3     AUX/Phantom1 LKP(2)

[Short]:< Blank >  [Long]:X_TV;PIP_Swap;X_Cancel
Change  TV to AV Input

4 AUX/Info DSM

The Cable/Phantom1 is a LKP or Long Key Press key. If the cable button is held down, the device index will temporarily change to TV and the PIP_Swap button will execute, and then the temporary device selection will be canceled.  This sets the TV to receive AV Input.  I could have done this without an LKP but this puts up a large block of text on the screen for 3 seconds, so I don’t want to execute this discrete if I’m just trying to insure that I’m controlling the DTA. 

The TV/Phantom1 is also a LKP to change to the tuner function.  There isn’t a discrete to select the tuner, but a CH+ will select the tuner if it was not previously selected.  However if it already was selected its going to change channels, so again I don’t want this to automatically fire if you are only pressing the TV button to regain control of the TV.

Another function you’ll see here is the Info button.  I’ve set up both a Macro and a DSM (Device Specific Macro) on this key. 

Macro :  
Aux/Info  SHIFT-Info

You’ll see that both defintions refer to Shift-Info.  You won’t find anything defined on Shift-Info.  I’m taking advantage of shift cloaking.  When the remote doesn’t find anything on Shift-Info, the shift flag is removed and the remote sends the Info button for the current setup code. 

If the Other-keygroup is set to AUX, pressing Info executes the DSM and sends the Info signal to the DVD/VCR. 

If the Other-keygroup is set to TV or CABLE,  pressing Info executes the macro, and the info key will send both the TV/info  and the CABLE/Info signals.


The ALL-On macro turns on the TV and the DVD/VCR and insures that the DVD/VCR is tuned to channel 3, and that the TV input is set to AV.


The rest of the keys that were defined in the IR file, merely add functions.  The confusing setup is now easily managed even by the guests who get the minimum instruction of "The dvd/vcr needs to be on to tune cable channels so use the all on button to turn the TV on and off."