Currently Viewing Posts Tagged “cordless phone”

WiFi Channel choice

WiFi IEEE 802.11b has a very limited channel (depend on country). In vary pack area with many WiFi Access point not all channel can be use at the same time. In North America, US State and Canada only Channels 1,2,3,4,5,6,7,8,9,10 and 11 are available for usage. In Europe Channel 1,2,3,4,5,6,7,8,9,10,11,12 and 13 can be use. In Japan only Channel 14 available for usage. The usage of each channel depend on country policy.
WiFi with base protocol IEEE 802.11b used Direct Sequence Spread Spectrum (DSSS) Modulation, which mean spectrum width for each usage is 22MHz wide for each station. This mean a station with 2437MHz Channel will be working on frequencies range of 2426MHz to 2448MHz. It will interfere 2 channel below and up of its channel. So effectively only 3 channel can be used without interfering each other which is Channel 1 , 6 and 11.
Channel : Frequency (Bold Channels = Recommended)
1 : 2412MHz
2 : 2417MHz
3 : 2422MHz
4 : 2427MHz
5 : 2432MHz
6 : 2437MHz
7 : 2442MHz
8 : 2447MHz
9 : 2452MHz
10 : 2457MHz
11 : 2462MHz
12 : 2467MHz
13 : 2472MHz
14 : 2477MHz

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Cordless phone and Wifi conflicts

There is a very strange thing happen between my Wifi connection and cordless phone.
I use D-Link WBR 1310 wireless router and WUA 1340 adapter.
I also have a cordless phone which works on 2.4Ghz. It is Vtech cordless phone.
When I take a phone call with this cordless phone, my wifi connection will be lost.
I also have another cordless phone. It is GE DECT 6.0 TC28223EE3.
It works OK when I use wiless internet connection.
I Googled it and got the answer.

802.11b and 802.11g use various frequency bands within 2.4GHz
802.11a uses various frequency bands within 5.8GHz
Cordless phones currently appear to come in 900MHz, 2.4GHz, or 5.8GHz.
Note that some “5.8GHz” phones will transmit in one direction using 5.8GHz, but in the other direction using 2.4GHz.

The wiless router is working on 802.11g. It is 2.4Ghz. It is same as my 2.4Ghz cordless phone.
So the problem appears.

Most 2.4GHz cordless phones are “spread spectrum’ – in other words, they stomp all over the range of spectra that your 802.11b and 802.11g want to use – and these wifi technologies more cooperatively use one portion of the 2.4GHz spectrum (generally user-selectable).

This paragaph answers my another question. Why cordless phone is OK, but wifi stops working.
So I know the problem, but how to solve it.
I have to use Wifi on 802.11g, because of my Wii and Nintendo DS need it.

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