[cisco-voip] Radio caused reboot of IP phones

[Leetun, Rob]

Hi Scott,

 

Here is the response from our radio guru.

 

Rob

 

"Yup, not unexpected at all.  What is happening is common with RF
equipment used around other electronics.  It is called Radio Frequency
Interference or RFI.  Radio transmissions can cause microprocessors and
other digital electronics to act very erratic and unpredictable.  It is
not uncommon to see microprocessor core devices either hang or re-boot.

 

There are a number of fixes for such problems:

 

1.  Remove the radio equipment from the other electronic device.  While
this is simple it is not always practical.

2.  Reduce the power output of the radio device.

3.  Use a remote or external antenna for the radio (almost the same are
removing the radio from the area.)

4.  Use a different RF frequency for the radio (another channel or
another band.)

5.  Apply RFI filtering to the device failing.  This is not simple.
Complex engineering and design changes are often needed.  But sometimes
simple fixes can be found:  RF chokes on cables going into the devices
(by use of ferrite beads and by-pass capacitors), proper grounding of
affected devices, and better shielding of those devices top the list. 

 

I am seeing more and more of these problems on a daily basis as more and
more things are controlled by electronics - even toasters, Li Ion
batteries, shavers and toothbrushes have microprocessors in them now and
are suseptible to RFI.   They are sometimes simple to solve but often
take work and prompt a device re-engineering.  Some things are just not
designed to work in a thick RF environment...

 

Not really a good answer but this IS the starting point (the proverbial
tip of the iceberg...)

 

Scott" 

 

 

From: cisco-voip-bounces at puck.nether.net
[mailto:cisco-voip-bounces at puck.nether.net] On Behalf Of Wes Sisk
Sent: Monday, March 10, 2008 2:53 PM
To: Scott Voll
Cc: cisco-voip at puck.nether.net
Subject: Re: [cisco-voip] Radio caused reboot of IP phones

 

Known issue and not much we can do about it.  Phone has to be
susceptible to RF interference by FCC rqmt.  Some phone models are
more/less susceptible by housing insulation, but all do reset with
enough RF close enough.

/Wes

Scott Voll wrote: 

Has anyone seen this before.

 

one of our sites uses Kenwood ProTalk radios.  if you key the radio the
IP phone (794x) phone reboots.  Totally reproducable.  Key the button
reboot.  

 

Is this a know bug?  anyway to fix it?  in the event of an emergency
when both phone an radio are needed, this could be really bad news!

 

TIA

 

Scott

 


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