Re: Has anyone ever use IR extenders with EC kit successfully? Which ones if so?

The short answer is 'no' ... however the following email exchange with a client who wanted to try the technology may be of interest ... 


--- Message Follows ---

Dear Client,

Sorry to hear that you are having interference problems.

First confirm that with both the Marmitek Powermid XL transmitter and receiver unplugged from the wall and with their batteries removed (as appropriate) that their is no interference present on the GN 9120 Telephone with Radio Headset.

If there is no interference with the Marmitek Powermid XL devices unplugged then plug them back into a mains socket and replace batteries (as appropriate).
If interference is still present then it will be necessary to locate the source.  This can only be done by removing power from each electrical appliance in your home in turn and to check whether mains interference is still present.  It may be that the device that is causing the interference is nearby in someone else's home.

As explained in my original email "experience has shown that 2 radio devices in very close proximity can interfere with each other. If this is found to be the case then usually the solution is to move the 2 devices further apart."  So try moving the GN 9120 Telephone and Radio Headset as far apart from the Marmitek Powermid XL transmitter and receiver as far as possible - without causing the Infra-Red to stop working.

Please let me know whether there is an improvement.


Yours sincerely,

Peter Hamlin [Tel: 0 (044) 1895 279162 Fax: 0 (044) 1895 279737]
Rehabilitation Engineer
North Thames Regional Environmental Control Equipment Service (NT RECES)
Alderbourne Rehabilitation Unit (Entrance 'C' - off Royal Lane)
Hillingdon Hospital NHS Trust
Pield Heath Road
Uxbridge
Middlesex

UB8 3NN
 
UNITED KINGDOM


--- Original Message ---
Subject: RE: Infra-Red (IR) Extender or Digital Infrared Repeater (DIR) 
Created By: Client 
Scheduled Date:  
Creation Date: 19/04/2009 18:47  
From: Client

Recipient Action Date & Time Comment 
    To: Peter Hamlin (hamp1al) 

Thanks for the website links and advice. After looking at the different devices offer I decided to buy the Marmitek Powermid XL and after I set it up as described in the manual I tried using it to use the phone and it seems to work, although in the headphones there is a lot of noise and interference so much that it is really difficult to hear someone talking on the phone. I doubt this could be because of the IR extender because the signal goes through. Is there anything that I should do to stop the interference?


Regards,

Client.


> Date: Thu, 26 Mar 2009 13:41:12 +0000
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> To: Client
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> Subject: Infra-Red (IR) Extender or Digital Infrared Repeater (DIR)
> 
> Dear Client,
> 
> Further to my visit yesterday with Jorge Petrone (Engineer, Possum Controls Ltd) to the installation of the GN 9120 Telephone with Radio Headset, I understand that you wish to be able to answer the telephone from other rooms.
> 
> It may be possible to do this using an Infra-Red (IR) Extender. An IR Extender is comprised of 2 units; (1) A Radio Frequency (RF) Transmitter that receives infrared signals that it converts to RF signals (which are transmitted). And, (2) a RF receiver which converts the RF signals back into IR.
> 
> Possum Controls do not at present include an IR Extender in their product range. Possum Controls Limited used to offer an IR Extender unit but it appears that this is no longer available. The reason for this is unclear. However the IR Extender may not have been 100% reliable.
> 
> The majority of domestic Audio Visual (AV) equipment uses modulated IR in the range of 36KHz ~ 40KHz; this frequency range should be supported by all IR Extender products. I have been advised that devices from Possum Controls Limited use a modulated carrier of 38KHz to transmit IR information. So theoretically an IR Extender should be capable of relaying IR signals between 2 devices from Possum Controls Limited - however I have not tested this.
> Note that IR Extenders do not work with some AV apparatus and models which use a IR frequency greater than 40KHz - for instance Bang & Olufsen (B&O) AV equipment.
> 
> In addition it is likely that IR extenders will use the RF frequency of 433MHz which may conflict with other 433MHz sources (e.g. wireless head phones, wireless speakers) - and these will diminish the range of an IR Extender - and any other device in the vicinity operating at 433MHz.
> The good news is that because the radio headset on the GN 9120 Telephone operates at a RF frequency of 1.8GHz this should not interfere with an IR extender.
> Having said that there should be no interference, experience has shown that 2 radio devices in very close proximity can interfere with each other. If this is found to be the case then usually the solution is to move the 2 devices further apart.
> 
> NT RECES is not in a position to recommend a particular IR Extender product as we have not tested any.
> 
> It is therefore advised that you try obtaining an IR Extender yourself, however as there is a possibility that you may not find the technology satisfactory, I suggest that you ensure that any IR Extender purchased is unwrapped CAREFULLY and its packaging retained - in case it needs to be repackaged and returned for refund.
> 
> 
> NOTES:
> 
> - When purchasing an IR Extender check whether additional transmitters are available. These will be necessary should you wish to use the unit in 2 or more rooms - other than the room containing the GN 9120 telephone.
> 
> - Check the maximum distance (range) that the Transmitter and Receiver can be placed apart from each other.
> 
> - Check that the IR Extender supports modulated IR in the range 36KHz ~ 40KHz; the greater the frequency range supported by an IR Extender the greater the probability that it will support all IR devices.
> 
> - A mains powered unit is probably preferable to a battery powered unit.
> 
> - Search the Internet for IR Extender or Digital Infrared Repeater (DIR)
> 
> - Marmitek range of infrared extenders at:
> http://www.reallycleverhomes.co.uk/acatalog/Marmitek_infrared_extenders.html 
> Comparison at:
> http://www.modushome.gr/multimedia/infrared-extenders.html 
> 
> - Knoll Systems:
> http://www.knollsystems.com/prod-infrared.html 
> 
> - Powermid Bi-Power & Powermid XL:
> http://www.letsautomate.com/ 
> 
> 
> Yours sincerely,
> 
> Peter Hamlin [Tel: 0 (044) 1895 279162 Fax: 0 (044) 1895 279737]
> Rehabilitation Engineer
> North Thames Regional Environmental Control Equipment Service (NT RECES)
> Alderbourne Rehabilitation Unit (Entrance 'C' - off Royal Lane)
> Hillingdon Hospital NHS Trust
> Pield Heath Road
> Uxbridge
> Middlesex
> 
> UB8 3NN
> 
> UNITED KINGDOM
>