RS-232 for Motorola DCT-2000/2200 ?
Eric Nielsen
> cable company and I notice it has what appears to be a 9-pin RS-232
> connector on the back, and sure enough, the data sheet on the web also
> claims the box has an RS-232 port.
>
> Does anybody know what it can be used for and how?
>
> Why? Well, for starters, I'm trying to rig my PC as a PVR and would
> like to be able to control the channel on the digital converter from
> the PC. I suppose I could rig up an IR controller, but that seems
> like such a kludge if there's an RS-232 port built in...
I've been wanting to do this for a long while, and this is what I know so
far through lots of scouring.
-The RS-232 port CAN be used to change channels. The AT&T Series 2 Tivo did
this.
-Your DCT-2000 needs a RS-232 port (not all have them)
-Your DCT-2000 requires firmware revision >= 7.54 (you'll have to wait on
your provider for this)
-Your cable provider needs to enable serial control for your box
specifically (call them, this can be done remotely)
-As of Feb 5, 2003, All series 3 Tivos are eligible for serial control of
the DCT-2000. Tivo will get the cable company to enable serial control for
your box if you wish.
Ok, this is all fine and good, what about controlling the channel with a
computer?
-I don't know if the cable required is straight through or null modem.
(keep a null modem adapter and a gender changer around)
-The DCT-2000 only needs pins 2,3,5 (TX,RX,GND) connected. (the Tivo serial
out is a 3 conductor TRS-mini plug)
-I can't find the link right now, but on a Tivo forum some guy posted the
byte sequence required to turn the DCT-2000 off and on. This was part of a
script that was to be run on a hacked Tivo.
What now?
-I know very little about RS-232 comm. I did try connecting to the box with
HyperTerminal, but that did nothing. I don't think anything that fancy is
needed, since the Tivo doesn't bother with carrier detect and all that flow
control crap. Anyone have experience writing raw data to a serial port?
-We need the control codes. What do you send over the serial line to
emulate CHUP or 7 or anything else on the remote? Maybe they are in the
service manual (HA!) for the DCT-2000. Another way to get them would be to
monitor and record what the Tivo sends out when it changes the channel.
I think the reason this idea hasn't gone very far is that we need one guy
who has the following:
-decent knowledge of serial communications
-a Tivo
-a desire to use his computer instead of his Tivo to change the channels
I'd be willing to paypal a couple of bucks to someone who can figure this
out, and I don't think I'm alone. If enough people me-too on this, it could
be worth someone's time. Here's to hoping.
Disclaimer: the users manual for the DCT-2000 says specifically not to
connect it to a computer. (oops) I don't know if this is because it will
mess up the box (doubtful), or the cable companies don't want to be pestered
with idiotic questions about this from subscribers (highly likely). Don't
do anything dumb.
As for using an IR transmitter/transceiver to control the DCT-2000 from a
PC, I'm doing that right now with an Actisys IR-200L. There are a couple of
devices that can do this. It is kludgy and takes some effort to set up, but
it mostly works. It's not perfect, and it will whiff on a command
occasionally. Lots of tweaking the signal timing/repetitions/delays/ etc
has gotten it working fairly well.