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2.4GHz-Friendly Phones?
da3dAlus writes "When I first bought my 2.4GHz wireless phone system several years ago, it was a rather new technology, and wi-fi wasn't even on the scene. Now it appears that all wireless phones are on the 2.4 or 5.8 GHz spectrum, and I've got neighbors with wi-fi (with myself included). While checking out new phones recently, I've noticed some are carrying a "802.11 Friendly" sticker. The question is, are there any trully 802.11 friendly phones? Has anyone really ever had a problem with these types of phones interfering with their wi-fi network?"
Mine 900mhz cordless phone even has spread spectrum. Works great, excellent range.
We had to stop using our brand new 2.4Ghz phones at work because our wi-fi stuff wouldn't hold a signal when the phones were in use. Keep in mind this was 2 years ago, haven't tried anything since.
So, I had a linksys wifi router and an AT&T 2.4 gHz phone... They fought like dogs! If the phone rang, wifi was out for at least 5 mins after you hung up. What a pain. I finally just bought a 5.8 gHz phone.
Don't violate your system's integrity, choose linux...
It interoperates. If it finds an open port on your wifi network, it will handover and use VoIP to complete the call.
:-)
This saves you money in the long run because VoIP is much cheaper cost-wise than typical cell service.
The main thing is to make sure that the phone is SAR-approved. You don't want those microwaves heating up your neural tissue!
24GHz?! Who the hell would need such a fast phone is beyond me! I have a 500MHz AMD in my desktop (Debian) and it works just fine, thank you.
Sincerely,
Pan Tarhei Hosé, PhD.
"Homo sum et cogito ergo odi profanum vulgus et libido."
My inlaws' 2.4GHz 'phone (sorry, can't recall the brand) totally screwed up their Linksys WLAN until I changed the WLAN channel (now it degrades link quality but doesn't drop it).
OTOH, My Panasonic 2.4GHz 'phone has never interfered with my Netgear WLAN.
I suspect that the 'phone brand has more of an effect than the WLAN brand.
I haven't bothered to change the AP to a different channel but so far it's working fine.
Worthy of mention is that the new handsets come with speakerphone and use three NiMH AAA cells instead of a shrinkwrapped battery with a lead. Plus they sound great and I don't have the problem I used to have on the older phone where the microphone was too sensitive and I heard background noise at too high a level in the earpiece.
Reviews with a twist! http://www.sardonicbastard.com
I've gone back to the older 900 MHz phones since installing a WiFi network at home. The WLAN didn't interfere with the 2.4 GHz cordless phones we had, but the phones knock the network down hard. I haven't heard anything about "802.11 friendly" labels on newer 2.4 GHz phones, but I'd be skeptical. If they work at all, they work by adaptively locating an empty part of the 2.4 GHz spectrum, and around many crowded residental areas, there ain't no such thing no mo'.
You can also get 5 GHz phones, too. Either 900 MHz or 5 GHz is fine, just keep 'em off 2.4 GHz.
http://www.vtechphones.com/vtechui/shop/productdet ail.cfm?itemID=1299
Reviews with a twist! http://www.sardonicbastard.com
I found the best way was to get a 900mhz phone. I have yet to find a 'decent' 2.4ghz phone. There is just too much stuff fighting for that space. Plus since 900mhz is 'old stuff' you can get em fairly cheap.
WiFi (802.11b) and 2.4GHz Phones almost always will clash -- but there is a good article on wifi planet that gives some things that can be done to lessen interference.2 191241/
http://www.wi-fiplanet.com/tutorials/article.php/
Of course, the best solution is a 900MHz or 5.8GHz Cordless Phone.
I have used my 2.4ghz phone while on my 54g wireless net with no issues. In fact my microwave messes-up my phone more than it does my wireless. I have two Linksys AP's running on a mostly wired net. They give me great coverage, sometimes too good... damn nieghobr with NetStumbler..oh well.
Everyone has a photographic memory, some just don't have film.
I haven't looked into it too much, but from what I understand newer 2.4ghz phones use an adaptive frequency response to get around interference from other devices. In essence they detect other devices on "locked" channels and maneuver their way through the mine field without causing any real problems for everyone else.
As for actual signal strength, the phones aren't usually the problem. 2.4ghz phones have 2.4ghz transmitters in the base station, but the phone itself is often just 900mhz. That being the case positioning the phones base unit away from any WIFI equipment can help, the same way positioning WIFI gear away from a microwave does.
You can probably just find more about the newer adaptive 2.4ghz stuff by doing a search with google...
-rt
900Mhz phones:
1) are inexpensive;
2) do no interfere with the 5Ghz and 2.4Ghz wifi channles;
3) do no interfere with Bluetooth;
4) are inexpensive;
5) will get better range because of the lower frequency used.
You are confusing me with someone who cares.
Household microwave ovens spew a lot of 2.4 GHz energy all over the band (enough that after looking at it on a spectrum analyzer, I no longer feel like pressing my face up to the window to see if the cheese on my pizza has melted yet).
However, they radiate only on alterating half-cycles of the 60 Hz line frequency. There may be a config option in your WLAN hardware's client utility to make it more resistant to microwave-oven leakage by forcing transmission of smaller packets. You'll lose some performance if you enable it, but it should keep your WLAN from going down altogether.
Dahlmann tightly grips the knife, which he may have no idea how to use, and steps out into the plain.
You mean like the 802.11a wireless networks?
But the first guy hit it right on the head. 900MHz phones are the best bet if you are running a regular wifi network and don't want interference.
Glonoinha the MebiByte Slayer
Thats cuz you are supposed to take your router out of the microwave before use!
No. 5.8GHz won't interfere with your wireless network. 802.11[bg] is at 2.4GHz, and 802.11a is at 5.4GHz.
I've tried a few 5.8ghz phones. They have horrible range and still pollute 802.11a. The quality is better, but not being able to leave the room with the base antenna doesn't really help.
Just stick to 900mhz for the best range and wireless reliability.
Urgo: "I want to live. I want to experience the universe and I want to eat pie!"
Jack: "Who doesn't??"
I have a PowerBook G4 which is equipped with an Airport Extreme card. The Airport Extreme (802.11b/g) has a feature called "Interference Robustness" which prevents any problems I would normally encounter using my 2.4GHz phone. Does anybody have any insight into how this works and does anybody know if any other wireless adapters include it?
I know there are other important speed-wise factors as well, the most important one being not the clock frequency itself but whether the chip has 64 bits or not. Nevertheless, I don't think anyone would ever need more than 640MHz.
Sincerely,
Pan Tarhei Hosé, PhD.
"Homo sum et cogito ergo odi profanum vulgus et libido."
I actually found a conflict between the wireless phones and wifi to be rather widespread. At my house we had a problem where if you were closer to the base station with your laptop than the phone was to its base station, the phone wouldn't always ring --- and then if you were further away with the laptop the phone would drop your internet while it was ringing. Can't say I've checked out newer phones... we've switched to iChat AV and cell phones for all our telecommunications needs :)
The world's only surviving livewriter.
You are doing nothing but using a low bandwidth device to pollute a frequency range that is better used on 802.11 networks.
2.4GHz phones does not mean that:
1. The sound quality is better. This is entirely dependent on the encoding algorithm the phone uses (if at all). The 2.4GHz is simply a carrier signal.
2. You get better range. You don't because 2.4GHz doesn't propogate as far.
And also, given that some 2.4GHz phones probably don't use spread spectrum, they are likely to interfere with several channels. At least bluetooth devices hop frequencies fast enough and are low power so they don't interfer.
The use of higher frequencies on phones I think is simply a product of marketing. You have people who hear about "2.4GHz" computers and think a similar increase in "GHz" will benefit their phone.
Good high quality 900MHz phones are out there, just keep looking.
So odds are a 5.8GHz phone would mess with the upper range of 802.11a.
Why not just overclock your phone? Put it up into the 20 ghz range and trump anyone who tries to start a conversation about them overclocking their Athlon. Weaklings.
I'm Rick James with mod points biatch!
^Quoting Rafiki from the lion king... The base has longer range because it has a higher power output. The physicaly properties of EM waves dictate that a 2.4ghz wave requires more energy to produce than a 900mhz wave. This is in part why AM radio stations are lower power, and the range is a lot better.
"And we have seen and do testify that the Father sent the Son to be the Savior of the World"
1 John 4:14
The cordless phone manufacturers have been playing quite a game over the past decade. They keep trying to get you to upgrade phones to a "higher" megahertz phone because they know that you are already being told by Intel to upgrade your CPU to a "higher" megahertz CPU.
;)
;)
;)
So, here's the thing. It's a general rule that as you go up in megahertz, the ability to penetrate walls goes down. Thus, the higher the megahertz, the lower the effective range. Consumer Reports did some tests here and showed that this carries over to reality. This is also why Verizon Wireless tends to have better reception -- they are primarily on the 850 MHz band instead of the 1900 MHz band.
So what have you gotten by upgrading to an "advanced" 2.4 or 5.8 GHz phone? Less range, although generally enough range to make it around a "normal" house.
Now, in order to produce a device that works in the 900 MHz, 2.4 GHz or 5.8 GHz band without a license the FCC requires you to be spread-spectrum.
There's some upsides and downsides here. First, some of the spread-spectrum devices, most notably older ones, didn't use very good spread-spectrum methods.
Second, in *theory* if everything's optimized properly, you can use some number of devices and they will all be perceived as "noise" to all of the other devices. So as you add more functioning devices in general, they will all start to experience interference. The problem is when devices using conflicting spread spectrum techniques are in use.
Third, microwaves and other such RF-heating applications, are covered underneath a different set of FCC rules, which generally are built around not causing your eyeballs to be fried overeasy (your eyeballs are the first thing to suffer damage from microwaves, which is why staring at the microwave window is not the world's brightest idea) Microwaves are supposed to be Faraday cages, but sometimes there's a leak. I'd start to wonder about my Microwave's safety if it started interfering with my WiFi, mind you.
Fourth, if there's interference and undesired performance, you have essentially no recourse. I've been thinking that they really should have allocated a frequency band that's reserved for only devices using a 802.11-standard protocol, but that decision really should have been made a long time ago. Oh, and if you start interfering with something important (That's the "Harmfull Interference" they speak of on the FCC warning on the back of a device) you can and will have government folks knocking on your doorstep. There have been documented cases of equipment interfering with aircraft navigation signals from the ground, which makes the airlines very unhappy and tends to get investigated.
I'm really wondering what the "Wifi-Friendly" cordless phones are actually. Especially given that VTech is the folks who are advertising it. As I've mentioned above, in *theory* any device on the 900 MHz, 2.4 GHz, and 5.4/5.8 GHz ISM bands (they are actually the same thing) shouldn't prevent each other from working and should just be perceivable as noise Also, *in theory*, one could "do better" by listening for 802.11b/g activity and actively routing around it. This is the big difference between Bluetooth 1.1 and 1.2. But that's more circuitry, so I'm not entirely sure if they are actually doing that, or they just put them in a test lab to see what happens. They'll probably insist that it took years of engineering time and it's a special feature, even if it's more the second.
I personally have just stuck to 900 MHz phones. Like I said, all things being equal, they tend to have longer range. Plus, I figure that having absolutely no interference is better than having a measured amount while the phone is in use.
Sure my WiFi uses 802.11b, which is 2.4 GHz, but there's some darn good reasons for why one should keep 802.11a around.
The main one is that 802.11a is usually faster than 802.11g at close range. So I have a halfassed
Gentoo Sucks
No more skull-to-the-microwave-window pressing for me either.
;)
Uhh... but you DO press your skull against the phone handset, which allegedly transmits a stronger signal (at least at that frequency)...
May I recommend a tin foil hat?
The other question is, will the 5.8 interfere?
I have an AT&T 5840 phone that uses 5.8GHz but if you read the fine print in the specifications, it also uses 2.4GHz:
All 802.11b/g devices use channels within 2412 MHz - 2483.5 MHz, so there is quite a bit of overlap there. When shopping around, I noticed that many 5.8 GHz phones actually use 2.4 GHz as well. In my limited use of 802.11b in the vicinity of this phone, I noticed no interference, but ymmv.
Interesting - that gives a window of about 8.3 milliseconds. (1/120th of a second, if I understand you correctly.) A full size packet takes about a millisecond to transmit at 11mbps, plus a few hundred microseconds for the ack. That should be well within the window.
Unfortunately, after repeatedly losing packets, most 802.11 gear will probably drop the transmission rate to its slowest rate: 1mbps. 1500*8 bits at 1 mbps is about 12 milliseconds (plus a few hundred microseconds for the header), which no longer fits in the window. In other words, by falling back on a more reliable transmission mechanism, 802.11 shoots itself in the foot.
Maybe if you can pin the rate at 11mbps and enable short headers (an option in the 802.11b standard supported by some hardware) it could work reasonably well, but fragmenting packets should help as well.
-jim
Given,
All of the 900 mhz advocates on this thread seem to think there is no interference I would like to interject and say that I do have interference issues with my 900 mhz phone and my 801.11 B equipment.
More specifically, I have a Panasonic 900 mhz gigarange telephone with some sort of digital spread spectrum technology (KX-TC1891B). The phone does not seem to impact my 801.11b equipment's (Linksys WRT54G) connectivity.
But, connectivity isn't everything.
As soon as I hooked a Hawking omnidirectional attenna onto my router I suddenly started hearing a beep on my computer speakers about every 5 seconds.
It about drove me nuts one day when I took the phone handset off the base unit and placed it in another room. I didn't realize that my phone was causing my computer to beep.
I thought something was dieing on my computer or that some program/virus was playing a cruel prank on me.
I must have rebooted that computer 20 times that day trying to isolate the cause of the beep. Never did.
Next day, put the phone back on the base unit and the beep went away.
Having discovered the source of the problem, I couldn't believe it, I turned the sound off via the computer's O/S, picked up the handset and no beep.
So, nowadays I have to turn the sound off on my computer before I answer the phone. Very annoying. But I paid a bundle for the two line phone, for which my wife was sorely irritated, so I guess I'm stuck.
Caution: Contents under pressure
In support of the comments about the handset running off batteries, and therefore having a shorter range, why do you think they're running 900 on the way back, and not 2.4 both ways? Because 900 takes LESS power to get the same range!
Thank you, come again.
47 MHz phones (you remember them, right? -- the *original* cordless) may be your best option yet! They're on such a low frequency that they don't have a chance of interfering with anything in your house, except maybe your neighbor kid's walkie-talkies or the garage door opener, and those are both very unlikely. Get a set with voice scrambling and you've got some privacy too. And lastly it has a terrific range and because it's analog, sounds good even when the reception is getting poor (you will get a little static, but that's better than drop-outs).
This absolutely true of most 5.8 phones out there. It takes more power to transmit at the higher frequency so in order to preserve battery life and keep the same range they handset actually talks at the 2.4 frequency.
Yet another reason why 900 Mhz is the best frequency so far allocated to cordless phones. It is high enough to allow reasonably short antennas and open space propogation efficiency, and low enough to still penetrate multiple walls at reasonable power levels.
My 900 Mhz handset seems to use a reasonably efficient 3" (~8cm) 1/4 wave antenna, while my base uses a nice 6" 1/2 wave antenna. Of course 2400 Mhz allows antennas that don't protrude out of even a small handset. In some applications, like very small handsets, this could be a significant design advantage, especially outside in rural areas where building penetration is least important and open space range most important).
For the old 46/49 Mhz phones the only privacy feature that I can recall is "frequency inversion" which produced Donald Duck quacking noises instead of speech. Some Uniden phones used this. However, such speech could still be monitored with the use of commonly available frequency inversion decoders. There were better "rolling" frequency scramblers for which decoders were not so easily available, but Uniden was not using those.
Keep in mind that the 46/49 Mhz phones were so low in power in comparison to modern phones that an eavesdropper needed to be much closer and/or have a much more sensitive receiver to pick up the broadcast. When 900 Mhz phones first came out they were regarded as less private until the first digital and then digital spread spectrum models were released. I am not aware of any viable method to eavesdrop on DSS calls.
Quite an experience to live in fear, isn't it? That's what it is to be a slave.
My suggestion, if you have the money to spend, is an engenius. We use a pair at work and aside from a flakey power system they get great reception and distance. Analog I believe. We get through 5 stories of concrete building plus the perimeter and into the neighboring buildings.
We tried most consumer products before purchasing these and nothing came close to the performance of these. The 5.8 ghz phones, from panasonic, could hardly get reception down the hall. All of the 2.4 ghz phones we tried couldn't reach another story. The 2.4 ghz I use at home can't reach to the other end of the house while our 900mhz (digital) can penetrate the house and surrounding acreage.
Finally, I can tell when my father uses our 2.4 ghz phone when I'm on the perimeter of the linksys 802.11b/g border. Depending on what my signal strength is, it'll drop or weaken.
Urgo: "I want to live. I want to experience the universe and I want to eat pie!"
Jack: "Who doesn't??"
Nice link. Frequency Hopping Spread Spectrum (FHSS) "hops" (jumps around to different frequencies). Direct Sequence Spread Spectrum does not. Direct Sequence is used more often on cordless phones. It is true that wideband is technically different, but Spread Spectrum could be seen as a form of wideband transmission since the whole point is to spread the signal over a wide range of frequencies to reduce detection.
Here's a quote from that article:
The use of these special pseudo noise codes in spread spectrum (SS) communications makes signals appear wide band and noise-like.
Quite an experience to live in fear, isn't it? That's what it is to be a slave.
Multiple reasons:
- Less people on it. Channels will be available until the end of time, and even if everyone in your neighbourhood has an access point, you won't have network problems.
- Less interest with wardrivers. While "security through obscurity" isn't the best idea if you're going to pick only one way to secure your systems, if you combine the fact that most people aren't looking for 802.11a networks with the fact that there are tons of open 802.11b and 802.11g networks you won't be looked upon as a potential victim nearly as much. It's not the end of security, but it's a good beginning.
- No protocol issues. 802.11b and 802.11g frequently have issues sharing, where the "g" features dumb down to "b" speeds if anything "b" is talking. This is bad in my opinion.
- Few, if any consumer devices in the 5GHz range. Nothing running in the house on 5GHz means nothing interfering with the network. Since everyone seems to be making 900MHz and 2.4GHz devices, including microwaves, telephones, and other things, using the currently lightly-used 5GHz area makes a lot of sense to me.
I was really sad that 802.11a never really made it to prime time in Linux while it was still commercially viable to manufacturers. I'd have bought into it in a heartbeat.Do not look into laser with remaining eye.
Unless you are unfortunate enough to live in North America, just make sure you get a DECT phone. These operate in the 1880-1900 MHz range, and are actually standards based.
:-)
From what I understand this frequency range is reserved in the US - so bad luck. You are stuck with stupid phones and the imperial system
I made the mistake of getting a Panasonic 2.4GHz phone. Complete crap, and has about 60% chance of killing your (and your neighbors) wireless LAN dead when you call someone. I'm just in the process of moving to DECT/GAP myself.
More info: http://www.dect.org/toptech.html
Ironically, this wouldn't be a problem for me except my stupid IBM Thinkpads think they are in the US, and won't allow me to use the extra channels that we are given in Australia. My WAP will go all the way up to channel 13 if I tell it I live in Australia - which is well out of the range the phone uses - but the Thinkpads limit me to max channel 11.
Zilch.
According to CR, The Panasonic KX-TC1484B gets both the #1 ranking in their review of 30 cordless phones (covering 900Mz, 2.4Ghz and 5.4Ghz phones). In addition, it receives the "Best Buy" designation, given that it rings in at $69.99 up here in Toronto...and a paltry, Froogled $29.99 right here: http://www.soundcitycorp.com/ECscripts/ECware.exe/ dcp?id=001&sku=Panasonic%20KX-TC1486&type=A1CN1&lc =EN
for our American cousins.
The CR comments indicated that in general, 900Mhz phones had the best sound clarity and battery duration (the Panasonic above lasts 16 hours).