[sci.electronics] VCR Plus+

gay@venice.SEDD.TRW.COM (Lance Gay) (01/16/91)

Here in Los Angeles, a new system for making VCR recordings of television
programs has been unvielded under the name of VCR Plus+ (a trademark of 
Gemstar Development Corp.).

It works this way -- first the user purchases a VCR Plus+ universal remote
control unit from a local electronics store.  This remote control unit is
advertised to work with most wireless VCRs and cable TV decoder units.  After
each program listing in the televsion section of the local newspaper
a 2-digit to 8-digit numer is listed.   To record the program simply enter
this program code into the remote unit, and it will send the appropriate
commands to your VCR to start and stop recording at the appropriate times.

The interesting part is: what algorithm is used to compute the codes?  I assume
that the code numbers are an encoding of 1) the TV channel, 2) the length of 
the TV program, and 3) the start time of the program. 

A few observations: The same program seen on the same day of the week does not
have the same code week to week.  The same program starting on the same 
day/hour but on two different channels does not have the same code.  
 
Listed below are some programs and times with their associated codes. I have
listed the same programs for four separate days.   All times are Pacific
Standard Time (I wonder if Daylight Savings Time is a problem?)  Is anyone able
to anyone come up with the algorithm?  Also, is this available anywhere else 
outside of Los Angeles?


     Taken from the Dec 30, 1990 and Jan 13, 1991 TV Times section of the 
                         _Los Angeles Times_
                                     

  Time  Chan Length  Program Name       02-JAN-91 03-JAN-91 16-JAN-91 17-JAN-91
------- ---- ------  ------------       --------- --------- --------- ---------
12:30 pm  2  30 min  Bold & Beautiful       43918     14222     23332     36678
 1:00 pm  2  1 hour  As the World Turns     31173     19777     28887     24833
 1:00 pm  4  1 hour  Another World          66869     87195     40055     19901
 1:00 pm  7  1 hour  One Life to Live       73173     75357     77177     73123
 2:00 pm  2  1 hour  Guiding Light          40918     19864     31210     17630
 2:00 pm  7  1 Hour  General Hospital       82918     60512     62158     51098
 7:30 pm  4  30 min  Hard Copy                 53        83       245       475
 7:30 pm 11  30 min  Current Affair          8227      2067      4413      2611


Lance J. Gay (N6BKQ)                         Internet: gay@venice.sedd.trw.com
TRW Systems Engineering & Development Div.   Phone: 213-764-9292
Redondo Beach, CA  90278