RE: IR Extender... Revisited!

["Ian B" <Ian@xxxxxxx>]

Sounds reasonable on the face of it. RS do receivers and transmitters
compatible with IRDA 1.1. The only thing not 'very' clear is the output
from
the remote and hence the receiver. It said  the receiver output was
compatible with an IC running an IRDA compatible demodulator. This is the
bit I would have to look seriously into. To read for yourself goto
www.rswww.com and search using IRDA. I think getting the remote and a scope
together would be the way forward there. I can also see some flat remote
batteries if I have anything to do with it. If I am to incorporate this
into
the 'SmartIR' devices I am building we will have to move reasonably
quickly.
I would also have to delegate some of the legwork so volunteers are wanted.
Legwork is finding out how the signal is composed and how to recreate it so
come on guys, running shoes on, lets go.

I will get a receiver and maybe a transmitter in the near future and have a
play. At the end of the day we don't care what is transmitted, just how it
is fired out of the emitter.

Ian



> -----Original Message-----
> From: KIFF, Graham, FM [mailto:graham.kiff@xxxxxxx]
> Sent: 16 August 2001 15:15
> To: 'ukha_d@xxxxxxx'
> Subject: RE: [ukha_d] IR Extender... Revisited!
>
>
> Here's some information I got directly from Pace on the subject:
>
> Hello
> I am sorry but I do not know of a universal handset or remote
> extender that
> will control your digital cable box due to a completely different
> system of
> I.R. modulation being used by the Pace cable receiver handsets .
>
> The system used was chosen by our customers ( the network
> providers ) and is
> a high speed system that gives some " future proofing "  of
the
> design . The
> system is  designed for remote keyboard use ( Web browsing ) and to
enable
> multiple handset to be used " simultaneously " as required
when playing
> games . This is because at some time in the near future the network
> providers  will offer these services .
>
> "Normal" handsets use a system of modulating (switching on
and off ) a
> carrier signal . The normal frequency of the carrier being in the
range of
> 35kHz to 60kHz..
>
> The system used by Pace uses TWTV protocol which is based on the IRDA
> standard that has been designed to enable computer peripherals to
> be linked
> without cables . ( This is not surprising  as modern digital cable set
top
> boxes contain a powerful micro processing systems and the Pace
> boxes are the
> first to also provide an integrated  cable modem within the box.) The
> handset data is transmitted as discrete pulses of IR - it is not
carrier
> based . The pulse rate is approximately 115kHz . The handsets have
> identification keys / tabs that  enable the receiver to identify
> the handset
> . Each key sends a 7 byte package of data within 600uSec (  the same
time
> that it taken to send only 1 or 2 bits of information with the
> normal system
> ) . This allows the data to be sent very quickly thus freeing time for
a
> second handset to jump in . The receiver software also adds a
> time stamp to
> the data to enable the games programmes to decide which handset
responded
> first . The system and protocols used are covered by patents hel
> d by TWO WAY TV LTD .
>
> I hope this answers your query but should you have any further queries
> please contact me again.
>
> Regards
> Craig Charlwood
> Technical Support - Service
> Pace Micro Technology plc www.pace.co.uk <http://www.pace.co.uk>
>
>
> > If it is just the modulation frequency then I could probably
> build it into
> > the current PIC based model. Each transmitter unit would be
> selectable for
> > IRDA or normal IR via a jumper. The only other hurdle would be
the
> receiver
> > unit. For IR they are nice off the shelf units.
> >
> > Does anyone know whether IRDA is simply a higher frequency and
are there
> > receivers available off the shelf. Ideally these would output a
> modulated
> > signal i.e. no carrier just like the TSOP 1838's we all know
> and love from
> > the current IR units.
> >
> > Ideas folks
> >
> > Ian
> >
> > > -----Original Message-----
> > > From: James Hoye [mailto:james.hoye@xxxxxxx]
> > > Sent: 16 August 2001 14:54
> > > To: ukha_d@xxxxxxx
> > > Subject: RE: [ukha_d] IR Extender... Revisited!
> > >
> > >
> > > > Stuart, I have exactly the same problem.  So if you get
any
> > > > information on this subject or anyone else has any
ideas, I will
> > > > be eternally grateful!
> > >
> > > Perhaps Mr Bird would look at making an IrDA compatibile
> version - is it
> > > just the modulation frequency that's much higher, or is it a
> completely
> > > different protocol (ie. no carrier, PWM, PPM or any other
acronym you
> care
> > > to imagine).  Someone (Keith) is probably now going to tell
me
> > > that carrier
> > > modulation is the same as PWM/PPM/whatever :)
> > >
> > > James H
> > >
> > >
> > > For more information: <a
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