[mythtv-users] Re: Transmission timing with ir blaster to cable box

[Steven Bennett]

I'll second this report -- I'm using lirc 0.7.0 pre2 snapshot, with a
DCT2224 cable box and the same Actisys 200L IR Blaster, and have the exact
same issue.

What's really interesting (and somewhat confusing) is that if you do the
send_once and give it a bunch of the same numbers, or do a bunch of
send_once commands for the same numbers in a script, it still doesn't
manager to get picked up by the receiver at all.  But the
send_start/send_end does just fine.  Looking at the blaster, it's clear that
any sequence of send_once inserts a noticeable delay in-between each
transmission, but the send_start transmits the signal continuously.  (Oh
yes, and it appears lirc transmissions adversely affect the system clock --
I've had it lose minutes during heavy testing...)

Unfortunately, while I've been experimenting with a new channel.pl script
to do a start-delay-stop-delay for each number, I've not been able to get it
to produce accurate results yet, although I'm close with a quarter second
delay in-between the start/stop.  (You have to use the system sleep command
instead of the perl one to get it to do fractions of a second...)

Still, sometimes it misses a number, and sometimes it gets it twice, and
more importantly what the cable box happens to be doing at the moment.

I can't really blame this on the blaster, though -- I see similar behavior
(dropped presses, occasional doubles) just using the standard remote.  But
there the user has visual feedback and it's just a mild annoyance.  With the
blaster, a mistake on this means you record the wrong channel.

And unlike the earlier threads in the archives discussing this cable box and
it's variants, mine does NOT have a serial port I can use to control the box
instead.

I haven't had the time to fool with this recently, but will be looking at it
again soon.  Anyone out there have any suggestions?

Thanks,
-->Steve Bennett


scut erky wrote:

> I've been configuring lirc (0.6.6) and ir blaster (actisys 200L) to work with
> a gi-motorola dct2000 cable box. I'm running mandrake 9.1 and myth 0.11 from
> rpms.
> 
> The lirc daemon starts fine, the lircd.conf is unchanged from the
> remotes/motorola/DCT2000 file and the irw and mode2 commands demonstrate that
> the ir blaster responds properly to signals from the cable box remote.
> 
> This trouble isn't with mythtv per se, but with the trasmission from the ir
> blaster to the cable box. I've searched all the posts and have seen hints of
> this trouble but no solution.
> 
> If I run 
>    %rc send_once gi-motorola-dct2000 CHUP
> I see lights from the ir blaster but no indication of response from the cable
> box (a little light lights up when it receives an IR signal)
> 
> It's only when I send a repeating signal like
>    %rc send_start gi-motorola-dct2000 CHUP
> 
> wait a few seconds, then
>    %rc send_stop gi-motorola-dct2000 CHUP
> 
> that I can get the cable box to respond to signals from the ir blaster. The
> distance between the ir blaster and cable box does not seem to affect
> anything.
> 
> So basically, this looks like the ir blaster is transmitting too fast for the
> cable box. And my question is, is there any way to slow down the transmission
> from the ir blaster?
> 
> Thanks for any assistance.