Re: IR for cable TV decoders ?

["Steve Bradley" <steve_ukha_d@xxxxxxx>]

Tim,

> 1. IR that most TVs, videos, CD players etc. use,
> 2. IR that the cable TV decoders use (is this IRDA, & what does
the "DA"
> stand for ?)
> 3. IR that connects mobile phones to laptops etc. (is this still IRDA
or
> something else ?)
> 4. IR used by some high-end hifi equipment
>
> Are 2, 3 & 4 all the same ?

No

> (Again all AIUI) but the problem with "repeating" IRDA is
the sourcing of
an
> appropriate IR receiver to feed signals into the distribution network
? Or
> the sourcing of an IR _and_ IRDA receiver ?

umm, it can be a problem, but not the biggest...

> Ok, so now to my suggestion,

<snip>

> Does this mean it's got a suitable IR(DA?) receiver & emitter to
allow it
to
> work with cable boxes ? Could this be cannibalised to remove the
necessary
> parts which can then be incorporated into a structured wiring IR
> distribution network ?

1) "Standard" IR remotes work by modulating a binary pattern onto
a carrier
frequency of around 38KHz.
2) *some* cable boxes and satellite receivers use IRDA, some use normal IR
(1)
3) Typically IRDA - some devices do support non-IRDA communications through
the IR port as well, though.
4) B&O kit falls under this category, and differs from (1) in that it
uses a
higher carrier frequency - up to about 120KHz I think. Some of the better
learning remotes can handle this, cheapo ones tend not to.

The remote you've seen might just mean it can deal with those cable boxes
that use more-or-less "normal" IR, not IRDA. Capturing and
replaying IRDA
signals is a whole different ball game. (But its not impossible... so I
could be wrong). For instance my cable box uses normal 38KHz signals and
any
leanring remote can handle it just the same as the TV etc. The receiving
part of learning remotes is a simple phototransistor - all the clever stuff
is done by the circuit it's attached to. Sometimes part of that circuit is
actually built into the same package as the phototransistor and filters out
any signals other than those around 38KHz - in which case what you're
suggesting wouldn't work.

You could try asking the company whether it'll work with IRDA
cable/satellite boxes. I'd be interested in the answer!

Cheers,
Steve