From: P729 (p729@cox.net)
Date: Wed Jul 23 2003 - 03:29:15 GMT-3
That's life in the unlicensed ISM (industrial, scientific and medical) band.
Manufacturers of equipment that utilize this band (well, reputable ones
anyway) are well aware of the potential for interference and typically take
steps to mitigate the effects of the interference. 802.11 radios are
supposed to operate on a "non-interference" basis, that is they're not
supposed to cause harmful interference yet be able to "take it." They
operate using DSSS (direct sequence spread spectrum) which allows them to
operate over a selectable, smaller sections of the ISM band. Devices
operating in this mode often "scan" their available "channels" during
initialization and select the one with the least interference. An Aironet
350 will do this (at initialization or config change) if you enable "Search
for less congested radio channel" under AP Radio Hardware. I would imagine
my Panasonic 2.4 GHz phones do the same each time I go off-hook. One might
suggest fiddling with which 802.11b channels are used, but it occurs to me
that this would not be very effective unless I could do something similar
with the phones (as with non-overlapping channels with adjacent AP's). The
phone documentation simply states "2400 to 2480 MHz," which encompasses the
entire 802.11b spectrum (2412 to 2462 MHz).
I'm using the aforementioned Panasonic 2.4 GHz phones and Aironet 350's in
two locations and am often camped on long-winded conference calls while
actively moving data wirelessly. Although I hear no interference and
perceive no performance degradation, it is quite obvious that my environment
is far from being "interference-free." The statistics panel of my Aironet
client displays an almost constantly incrementing count of "PLCP CRC
Errors," whose incremental rate I can readily influence by taking the phone
off-hook and initiating a conversation. But my MAC CRC errors increment at a
far lower rate, indicating, to me at least, that the radios are doing their
job with retrying, etc.
Regards,
Mas Kato
https://ecardfile.com/id/mkato
----- Original Message -----
From: "Pratt, Jeremy" <JPratt@coh.org>
To: <ccielab@groupstudy.com>
Sent: Tuesday, July 22, 2003 3:58 PM
Subject: OT: wireless and 2.4 ghz phones
I have been tasked with making the CEO and CFO's house wireless. As soon as
I walked in the door I found 4-5 2.4 ghz wireless phones being used. Has
anyone run into this issue before and how did you deal with it? .11A is an
option but I can only install one A/P at one end of the house and .11a wont
be able to make it the distance required.
Any help is appreciated.
Jeremy Pratt
Network Manager
CCNP, CCDP, CCSA, CCSE
City of Hope Medical Center
626.471.7145 - Office ext 65145
626.423.5424 - Pager
626.483.6083 - Cellular
626.256.8688 - Fax
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