You need to disable broadcasting of SSID.
Ssid broadcast
This is assuming that there is no outside access to the Ethernet network such as a Internet connection. If there were then firewalls would be needed to prevent a outside intrusion of the network. In addition to physical access security, a wireless network requires authentication and encryption to prevent unauthorized devices from connecting to the wireless network or capturing and decoding the data that is being transferred via a wireless network connection. If the wireless network has outside WAN access then you would also need firewalls as with the Ethernet network.
To prevent collisions.
Disabling the SSID Broadcast.
It is prevent all connected network cards sending at the same time.
Isolation
It uses a 128-bit pre-shared hexadecimal key to prevent unauthorized wireless access.
One major disadvantage of wireless networks is that they are hackable from the outside. Security measures are available to prevent or reduce the attacks.
use wireless encryption. for example, WPA or WEP (http://en.wikipedia.org/wiki/Wifi#Network_security)
most pepole would says yes as you may want to do personal banking and such and is someone has access to your network you can be prone to someone peeking in to what you do online
To avoid interference from devices such as wireless telephones you need to switch the channel your network uses. How you do this varies depending upon which make of router you are using. In general you would log into the router via a web browser, change the channel (usually under Wireless or Network settings) and then save your new settings. You may have the option to select Automatic channel selection which may be suitable for your needs.
An network access point is where you can wirelessly or wired (depending on the router) gain access to network capabilities it is connected to (eg. internet, domains, remote desktop). The access point when wireless has a WEP/WPA authentication key to prevent unwanted connectors from gain access to those privileges mentioned. The connection goes from the internet modem, then to router (the access point), then to the device you wish to gain network for (whether wireless or wired)