Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!sharkey!clmqt!lopez!flash
From: flash@lopez.UUCP (Gary Bourgois)
Newsgroups: sci.electronics
Subject: Re: Cable Remote Frequencies
Message-ID: <850@lopez.UUCP>
Date: 5 Oct 89 17:52:24 GMT
References: <15939@dartvax.Dartmouth.EDU>
Organization: Great White North/UPLink, Marquette, MI
Lines: 46

sean@eleazar.dartmouth.edu (Sean P. Nolan) writes:

>Hey there...

[wants to build a TV remote control and save CATV charges]

>But I don't know the whole set of frequencies, and trial-and-error doesn't 
>seem like a pleasant task. Sooo, if anyone out there has a list of standard (if
>in fact they ARE standard) frequencies that these boxes respond to, I'd

They are not "frequencies" exactly, they are PULSES.  and there are NO
standards.  By pulses, I mean short ones for digital 0 and longer ones for
digital 1.


>really appreciate an email note.  If not, I'll go with the trial and error
>method. *grin*

Because we are dealing with pulses of varying duration, a simple oscillator
will not suffice.  You hit it lucky with the 7, which in your box is
probably all 0's or 1's or is a default "in the middle" digit.

Trial and error? 

You do not have to go THAT far.  There are other solutions.  

Solution # 1 Find the
manufacturer of your cable box (jerold, General Instruments) etc.  That
company WILL sell you a remote control, for about $25.  I know; one of
mine got melted with a hair dryer.  I got a replacement from the
Distributor and NOT the cable company.

Solution #2  Purchase one of those "trainable remotes" which "learn" the
codes. This is more costly.

Solution #3  If you WANT to build one, get an infrared detector.  Connect
it to an oscilloscope.  set bandwidth appropriately and read the output.
Build an IC pulse circuit using diodes to program the 0's and 1's.
Recommended more for a learning experience.  I would go with Solution 1
myself.... 

-- 
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