# How does 921 talk to DPP44 Switch?



## FrequentFlyer (Sep 22, 2004)

Can anyone explain how the 921 communicates with the DPP44 switch? Is it by voltage changes, tones, or some other technology? I really need to figure out why my 921 gets into a certain error condition, and I am suspecting maybe it is due to communication problems with the switch as one possibility. It is a long cable run but well under 200 feet; maybe 120 feet. I was considering an amplifier, but would this even affect the communication between the receiver and the switch?

Also, can an amplifier be on the same line as the power inserter for the DPP44 if I need an amplifier at some point?


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## moviegoerman (Aug 18, 2004)

FrequentFlyer said:


> I was considering an amplifier, but would this even affect the communication between the receiver and the switch?
> 
> Also, can an amplifier be on the same line as the power inserter for the DPP44 if I need an amplifier at some point?


Make sure you have nothing on the power inserter line! I had a surge protector after the power inserter and it messed up my 721 reception. You might want to run your power inserter to a room with no tuner and then put amplifiers on the other lines with tuners, but I can't see why you would need them if your under the suggested line length.

Did you use new cables? Recheck all your connectors. Do some receivers work and others don't? Are you failing to get only certain satellites or is the entire output from the switch not working? Could it be a bad switch? Lightening?

Here is how I've got my DPP44 installed with a 921 and a 721... See attached imaged.

http://www.dbstalk.com/attachment.php?attachmentid=2497


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## FrequentFlyer (Sep 22, 2004)

movergoerman, what is your longest cable run? I am finding that my longest run is causing me problems, and now I am wondering if the 200 ft advertised limit is really possible, and if a long run can cause problems. I took a problematic receiver and moved it to a spot closer to the switch on the same cable (at the one junction point in the cable) and it worked fine. This is on a brand new RG6 cable that I just had RE-RUN yesterday because of the problems I was having that I had attributed possibly to the cable. So I know it is not the cable itself but perhaps the distance ...


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## Pepper (Mar 9, 2004)

To reach maximum length without excessive signal degradation, that new cable you ran needs to be DP compliant, meaning it's rated for the bandstacking which uses higher frequencies (up to 2150MHz) than standard RG-6 is rated for and it must pass the 22KHz tone for DiSEqC. Everything needs to be compliant including diplexers, ground blocks, barrel connectors, amps, surge protectors, etc.

You can get by with lower quality cable on shorter runs.


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## FrequentFlyer (Sep 22, 2004)

Pepper, it says "RG 6 High Performance 2.25 GHz Digital Cable". Do you think that should be adequate?


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## SimpleSimon (Jan 15, 2004)

FrequentFlyer said:


> Can anyone explain how the 921 communicates with the DPP44 switch? Is it by voltage changes, tones, or some other technology?


Digital commands. IIRC, they're modulated into the 22KHz tone.


FrequentFlyer said:


> Pepper, it says "RG 6 High Performance 2.25 GHz Digital Cable". Do you think that should be adequate?


Yes - plenty good. DishPro "only" goes up to 2100MHz (2.10 GHz).


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