Communicating with RS 15-1994 over SERIAL

[classicsat]

Read the last of:
Using a PC to control a remote.. or as a remote

At miniumum, I believe you need two chips (CD4051 I figure, t oclose the matrix), and you probably don't need a universal (although they are cheap), and have the micro close the contacts based on the VCR or other cable command signal it receives.

[The Robman]

Why do you think an old 3-wire interface UEI remote will include the setup code for you cable box?

Just FYI, 3-hole remotes like the 15-1918 and 15-1919 can be modified to also have a regular 6-pin JP1 connector, thus giving you the ability to add the required code using the JP1 tools.

Conversely, it would probably be quite simple to figure out how to modify 6-pin remotes like the 15-1925 and URC-7070 to include the old 3-hole interface (as all 4 remotes have exactly the same processor, with the same firmware, onboard).

I don't know when UEI started using EEPROM chips in their remotes, but in theory any 3-hole remote with an EEPROM can be converted into a 6-pin JP1 remote.

[jon_armstrong]

Jack,

Here a couple of thoughts. Do you have a wired IR distribution system or RF remote extender?

If it's wired, make sure both cable STB's are "hidden". Put individual IR emitters on the the two cable boxes. Use a DPDT relay to select between the Tivo and the wired distribution system. Also put a DPST relay on the cable box that doesn't have the Tivo. Get two x10 appliance modules to power the relays. Get an IR543 to convert IR to x10.

Then build the macros to select the cable boxes that make sense. I built a two zone IR distribution system that way, although I control the relays with a different I/O device. I found in my wired system that if I didn't lift both conductors, I got a lot of IR noise which makes sense since you are unbalancing the transmission line.

I have also used the same concept with the little RF pyramids. Just connect them to appliance modules and turn Off the ones you don't want transmitting.

The total cost is about ~$50, assuming you already have a wired system or the RF repeaters.

[Jack_Pollack]

Wow! You guys are great with all of your help.

What kind of cable box is it? Are you sure the cable box doesn't have a configurable unit number that would solve the whole problem?

The cable boxes are Pioneer Voyager and a Scientific Atlanta 3100. There are no 'unit number' switches on the box, and I don't see any way to set a device number through the menus. I have also googled this with no luck.

You said the LR remote is a Pronto. What's the BR remote?

The BR remote is also a Pronto.


I love johnsfine's idea about changing the frequency, then converting it back at the cable box. When I got home late last night and read all the posts I though I had come up with a great circuit based on this:
Distort the Pronto transmission frequency. Use a Sharp IR module (Radio Shack pn 276-137) to remove the distorted carrier. Then use a 555 clocking at the correct frequency ANDed with the clean IR data.

Looking at the Pronto data the second word for my learned cable box codes is is '0048'. If I am not mistaken this would indicate that the cable box IR carrier frequency is 72Khz

This idea was simple, elegant and did not require a microprocessor. Life was good until I woke up in the middle of the night and realized that this would solve the BR box control problem from the LR, but If I were in the LR controlling the local box the BR would receive the undistorted signal, remove the 72Khz carrier, then re add it. This of course would effect the BR box.

Is there a IR demodulator that won't pass 72Khz? The Sharp/RS unit says 38-40Khz but appears to demodulate the cable box remote just fine. Either I am mistaken about the carrier freq, or it has a much higher bandwidth then specified. If I can find a demodulator that has a very narrow bandwidth I can transmit the BR distorted frequency in its range, but the unmodified cable box IR signal won't pass through.

classicsat idea is interesting and worth exploring if I can't get the previous problem solved.


jon_armstrong I appreciate the idea, but this won't work for me for several reasons:

1. I am already using the IR/X10 system and have used all 16 addresses (actually I could use a few more).

2. The local equipment in each room is directly controlled through the built-in IR window int the equipment. The IR repeater system I have set up receive in room A and transmit in Room B, and vice versa.


Once again, all your help and ideas is greatly appreciated.

[johnsfine]

Scientific Atlanta 3100. There are no 'unit number'

Correct. Scientific Atlanta boxes have no unit number in the IR signal.

Use a Sharp IR module (Radio Shack pn 276-137) to remove the distorted carrier. Then use a 555 clocking at the correct frequency ANDed with the clean IR data.

I'm only guessing at what you mean, but I think you're saying remove the modulation from all IR signals across a wide band and transmit remodulated everything recieved at the Scientific Atlanta's IR frequency (which is 57.6 Khz). As you seem to have figured out that will transmit in situations where you don't want it to.

Since I thought you were using a microprocessor, I assumed it was easy to recognise the distorted IR and only retransmit when the incomming signal is the distored one.

Looking at the Pronto data the second word for my learned cable box codes is is '0048'. If I am not mistaken this would indicate that the cable box IR carrier frequency is 72Khz

That 72 is a wavelength in weird units, it is not a frequency. The units are around 241 nanoseconds, so 72 units is around 17.4 microseconds, which is pretty close to the 57.6Khz I know from other sources.

realized that this would solve the BR box control problem from the LR, but If I were in the LR controlling the local box the BR would receive the undistorted signal, remove the 72Khz carrier, then re add it. This of course would effect the BR box.

I don't have a clear enough idea of your IR distribution system, or of the flexibility you need in sending directed signals.

If you don't block the IR distribution system from sending to a particular cable box then any correct signal intended for the other box will reach that one. If a box receives signals only from the undistorter and not from the distribution system, that helps only if the undistorter won't pass the original signal.