The required Eb/No (SNR or SINR) for 54Mbps 802.11g is a lot (*LOT*) higher than for any modulation that one of the 'proprietary' 2.4GHz phones use. You can think of this as "better sensitivity" if you wish. (It isn't, but the concepts are somewhat similar.)

the DSSS modulation envelope also makes it easier / cheaper to run 'high power' (100 - 200mW). It would not surprise me if the DSSS modulation in the phone/base station was constant (not packet-based) (*) while a phone call is in-progress (or the phone is off-hook).

If the above is accurate (I'm guessing, but not reaching) then the high-power 'phone' signal will effectively set CCA on any 802.11b/g receiver in your home, preventing them from transmitting. If one does get to transmit occasionally (for whatever reason), then the ability of another 802.11b/g receiver to decode the packet in the face of the greatly increased noise floor is... nominal at best.

Technically the 'no transmits due to CCA' is not 'interference', and the DSSS (or FHSS) modulation envelope won't be coherent to the 802.11b/g receiver, so its "noise" not "interference" as well.

Jim

(*) with a timeslot-based protocol for the various handsets

On Jan 23, 2006, at 4:31 PM, Mike Burgess wrote:


I've found it takes something pretty powerfull to
knock a phone off, but nearly anything will kill
802.11g



--- Jack Unger <[EMAIL PROTECTED]> wrote:


If you suspect interference between an access point
and a phone system,
just turn one system off and see if the interference
goes away.

jack



Victor Caballero wrote:

I am curious about what people are running into
with wifi and 2.4ghz phones
interference.

Some people say they have no problems, others have
all sorts of problems.  I
am having some unexplainable problems(static on
phone, wireless disconnect)
and wonder if it could be the problem.

Any advice or recommendations appreciated.



Victor Caballero
Caballero Consulting Company
[EMAIL PROTECTED]
626.585.1379
Www.TheTopDeal.com




--
Jack Unger - President, Ask-Wi.Com, Inc.
Serving the License-Free Wireless Industry Since
1993
Author of the WISP Handbook - "Deploying
License-Free Wireless WANs"
True Vendor-Neutral WISP
Consulting-Training-Troubleshooting
[EMAIL PROTECTED]  (818) 227-4220
http://www.ask-wi.com




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