[time-nuts] ANFSCD - Synchronizing time in home video recorders

Bill Hawkins bill at iaxs.net
Sun Feb 5 20:35:09 UTC 2012


Thanks for the info, Clint.

Seems like the only way to get my four Panasonic DVRs to synchronize
time is to analyze the I/O of the micro in the DVR, write interface
and HMI specs, and replace the micro with one that can talk to my
SNTP server. (Added two DVRs back when NASA was launching shuttles.)

This would have the added benefit of fixing the scheduling bugs and
make finalizing automatic for a full disk, rather than the five clicks
it takes now.

One day, the lack of sync every week will get to me, and I'll start
this project, but I don't think I'll live to finish it.

Bill Hawkins


-----Original Message-----
From: Clint Turner
Sent: Thursday, February 02, 2012 4:10 PM

-----%<----- Off subject stuff snipped

I, too, have an older (Philips) DVR that has lost its time sync since 
the analogs went dark.  For a while, I used the XDS time code that 
happened to be in the vertical interval of one of its standard 
definition DTV PBS station's sub-channels (received on a set-top box and 
modulated onto a TV channel to which the DVR would "look" for its time 
code) but this has code since been dropped.

Before I discovered this, I dug up the line 21 (IIRC) code 
specifications and noted that even a PIC could probably generate the 
proper code, synchronized either from a GPS or a WWVB receiver.  I'd 
thought about putting it on multiple lines and then RF modulating it for 
the DVR to see, but lost enthusiasm after I discovered the time code on 
the sub-channel.  Since that went away (about a year ago) I've just 
remembered to set the clock once a month, not being able to quickly find 
the specs for the time code again online...

73,

Clint
KA7OEI




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