Getting Poor Signal or No Signal on Cisco VOIP Router
From Asterisk Australia
Q. What should I do if I'm getting poor signal or no signal?
Low or poor signal is mainly caused by four major factors: </p>
- Distance
- Obstructions
- Interferences
- Transmit Rate on the Access Point and/or the Wireless Adapter Not Set to Auto
Solving Distance-Related Problems
Keep in mind that wireless devices have limitations when it comes to their range. For devices running on 2.4 GHz, the range can go up to 100-150 feet. If your wireless network is too far from its range, consider relocating the devices. One important thing to remember is that distance is directly proportional to signal strength. The farther you are from the Access Point, the lower the signal. To check if you're getting a stable connection, perform a continuous ping. If you're getting replies most of the time, this means the connection is stable. If it times out majority of the time, the connection is not that stable. For instructions, click <a href="#performing">here</a>.
Note: If you're using an SRX and/or SRX400 device, the range is thrice that of Wireless-G. If they are using SRX200 devices, the wireless range is twice that of Wireless-G. If the customer, on the other hand, is using a Wireless-N device, the wireless range is four times compared to Wireless-G.
<a id="performing" name="performing"></a>Performing a Continuous Ping
Note: This article assumes that the LAN IP Address of the wireless router is 192.168.15.1. If you've changed the router's IP Address, that's the IP Address you'll be pinging.
Windows 2000/XP
Note: To perform continuous ping using Windows 98/ME, click <a href="#98/me">here</a>.
Step 1:
Click Start, then Run.
Step 2:
When the Run window opens, type "cmd" in the Open field, then click OK.
Step 3:
When the MS DOS Prompt appears, type "ping 192.168.15.1 -t" or the IP Address of the wireless router then press [Enter].
Step 4:
Take note of the percentage of replies you're receiving.
<a id="98/me" name="98/me"></a>Windows 98/ME
Step 1:
Click Start, then Run. A window similar to Step 2 will appear.http://www.cisco.com/image/gif/paws/108654/3984-009.png
Step 2:
Once the Run window appears, type "command" in the Open field, then click OK.
Step 3:
When the MS DOS Prompt appears, type "ping 192.168.15.1 -t" or the IP Address of the wireless router then press [Enter].
Step 4:
Take note of the percentage of replies you're receiving.
Going Around Physical Obstructions
Wireless networks are also susceptible to obstructions that may lead to low signal. Often, the signal gets reflected, refracted or absorbed by the obstruction.
Common obstructions are:
- Cabinets
- Mirrors
- Glasses
- Metal objects
- Thick walls and ceilings
If you have any of these objects between your wireless adapter and access point, consider relocating your access point somewhere high to get around the obstruction.
Encountering Wireless Interferences
Neighboring wireless networks or any appliance that operates on the same frequency as your wireless device (e.g. 2.4 GHz) may cause interference and therefore may affect your wireless connection and signal.
Common sources of interference are:
- Neighboring wireless networks
- Microwave ovens
- 2.4 GHz cordless telephones
- Bluetooth devices
- Wireless baby monitors
To solve the problem, change the channel and SSID on your Access Point. Preferred channels to use are 1, 6 and 11 since they're considered non-overlapping channels.
Changing Channels
The 802.11b and 802.11g standards use the 2.4 Gigahertz (GHz) band. With this of frequency, 802.11b and 802.11g equipment can encounter interference from microwave ovens, cordless telephones, Bluetooth devices, and other appliances using the same band.
An important concept to note regarding channel assignments is that the channel actually represents the center frequency that the transceiver uses within the radio and access point (e.g., 2.412 GHz for channel 1 and 2.417 GHz for channel 2). Remember that there's a 5 MHz separation between frequencies and that an 802.11b signal has a frequency spectrum or range of approximately 30 MHz. A signal falls within about 15 MHz both sides of the center frequency which results to an 802.11b signal overlap when using several adjacent channel frequencies. This leaves you with only three channels (channels 1, 6, and 11 for the U.S.) that you can use without causing interference between access points.
To change the channel on your wireless router, click <a href="../../../../en/US/products/ps10024/products_qanda_item09186a0080a3562c.shtml">here</a>.
Making sure that the Transmit Rate on the Wireless Router is Set to Auto
Changing the Transmit Rate on the router allows the device to work at a specific speed for wireless transmissions. The default Transmit Rate is Auto with a range of 1 to 54Mbps.
The rate of data transmission should be set depending on the speed of your wireless network. You can select from a range of transmission speeds or keep the default setting, Auto. This will allow the router to automatically use the fastest possible data rate and enable the Auto-Fallback feature, which will negotiate the best possible connection speed between the router and a wireless client.
Note: If the transmit rate on the router or the adapter is not set to Auto, the Auto-Fallback feature will be disabled. If the Auto-Fallback is disabled, you will not be able to experience the maximum range of the wireless router as it will not be able to adapt to the environment's condition.
Linksys does not recommend changing the transmit rate of the router other than the default value. Changing the Transmit Rate will shorten the range of the wireless network as shown in the sample diagram below.
Using Range Expander, Wireless-N, SRX Devices, and/or High-Gain Antennas
- If you're not yet using Linksys' Pre-N or SRX Technology, you may want to use the following Wireless Routers, Access Points and Wireless Adapters:
- If you're using wireless devices such as:
WRT54G
WRT54GS
WAP54G
BEFW11S4
WAP11
You may use the WRE54G, a Wireless-G Range Expander. Unlike adding a traditional access points to your network to expand wireless coverage, the Wireless-G Range Expander does not need to be connected to the network by a data cable. Just put it within range of your main access point or wireless router and it "bounces" the signals out to remote wireless devices.
- If you're using wireless devices such as:
WRV54G
WMP54GS
WMP54G
WET54G
WET54GS5
You may use an AS1SMA to relocate your Wireless-B or Wireless-G antennas to avoid obstacles and improve signal strength.
- If you're using wireless devices such as:
WRT54GS
WRT54G
WAP54G
BEFW11S4
WAP11
HGA7T (High Gain Antennas)
You may use an AS2TNC to relocate your Wireless-B or Wireless-G antennas to avoid obstacles and improve signal strength.
- If you're using wireless devices such as:
WRV54G
WMP54GS
WMP54G
WET54G
WET54GS5
AS1SMA (Antenna Stand)
You may use an HGA7S to increase the wireless signal of your Linksys Wireless-G or Wireless-B devices.
- If you're using wireless devices such as:
WRT54GS
WRT54G
WAP54G
BEFW11S4
WAP11
AS2TNC (Antenna Stand)
You may use an HGA7T to increase the wireless signal of your Linksys Wireless-G or Wireless-B devices.
