JP1 Remotes

Julie5040 · Joined: 17 Nov 2003 Posts: 32

Jason,

We have success (well kinda)!!!

Ok, the scoop this time is:
Code #1 works via IR 100% of the time and via RF 0% of the time (not at all). Code #2 works via IR 100% of the time and via RF 90% of the time. Code #3 works via IR 100% of the time and via RF 99% of the time (which is good enough for me!).

HOWEVER, there is one exception, I thought the command centers were all the same, but evidentally I was WRONG! The working code only worked with the one for all command center which came with my 9910. The older 15-1995 command center would only control the DVD 25% of the time with Code #3 loaded. I called my friend (who also has a 1995) and asked her to bring over her command center and remote for testing. After taking flack as to why I was "stuck on this crazy stuff", she brought over her 15-1995 and her command center. They both worked exactly as mine did (i.e. her command center only controlled the DVD 25% of the time, but her remote controlled the DVD 99% of the time through my 9910 command center).

Unfortunately, I left the two 15-2117s in my brother's car and do not have them here to play with. Thus, I cannot tell you till tomorrow if the command centers from the 2117 also work as well as the one from the 9910 (I am assuming they will).

Also, while on the 2117 suibject, since the 15-2117 does not control the DVD correctly via RF, can I load Code #3 into that as well?

Julie

P.S. Jason thanks for all the hard work, your a genius!

Mark Pierson · Posted: Wed Nov 26, 2003 6:36 am Post subject:

johann83 · Joined: 03 Aug 2003 Posts: 66 Location: Pittsburgh, PA

The Robman · Posted: Wed Nov 26, 2003 12:45 pm Post subject:

Just FYI, if you want to make the data frame repeat 3 times for NEC1 signals, you can set bit1 of the parm byte (ie, the first fixed data byte).

In this case the fixed data is "00 DF --" (where it doesn't matter what's in the 3rd byte). The parm byte is the first byte, so it's current value is "00", which in binary is "00000000". If you set bit1, the binary becomes "00000010", which in hex is "02".

So, if you change the fixed data to "02 DF DF" the data frame will repeat 3 times before the signal changes to the normal repeat pattern.

For further details of how the parm byte works, see this thread...
http://www.hifi-remote.com/forums/viewtopic.php?t=169
_________________
Rob
www.hifi-remote.com
Please don't PM me with remote questions, post them in the forums so all the experts can help!

gjarboni · Posted: Wed Nov 26, 2003 4:58 pm Post subject:

Julie5040 · Joined: 17 Nov 2003 Posts: 32

Mark Pierson · Posted: Wed Nov 26, 2003 8:03 pm Post subject:

mr_d_p_gumby · Posted: Wed Nov 26, 2003 9:28 pm Post subject:

Sorry for the delay in replying; was out of town on business.

AGC is Automatic Gain Control, as johann83 stated. What is relevant here is that an AGC has a finite response time, and during this time period, the signal may be distorted. Remember that the RF receiver is suddenly going from no-signal to full-signal, and that response time is likely to be at it's maximum during this period.

A similar effect happens when the digital signal is AC-coupled (i.e., connected through a capacitor). The circuit will have a response time as it reacts to changing signals, and this too may cause distortion.

The whole idea behind my theory here is that the NEC1 protocol only sends meaningful data during the very first frame, and the RF receiver may be distorting this frame so that the DVD's IR decoder rejects it. Sending a fairly long carrier burst first gives the RF receiver time to adjust to the signal before sending the real first frame of the NEC1 signal. At the same time, the long burst is rejected by the DVD's IR decoder regardless of whether it is distorted or not.

The results that Julie is getting would seem to indicate we're on the right track here.

I'm not sure how long the burst would need to be. That's something that would have to be experimented with. It absolutely must be something the DVD's IR decoder will always reject. It could even be a different carrier frequency. Perhaps the 1995 RF receivers have a longer response time and may need a longer burst.

Also, I don't know exactly how long a gap shoud be inserted after the burst before sending the NEC1 frames; that is mostly a function of the way the DVD's IR decoder works (how much "dead" time it needs before it can decode a new signal). My hunch says to make it about one frame's worth, but shorter may work too.
_________________
Mike England

JP1 Group at Yahoo!, JP1 Files Area

The Robman · Posted: Thu Nov 27, 2003 9:37 am Post subject: