Why my 3G router can't conect to modem, and light signal is off

Signal is beneath a threshold voltage supplied to the diode.

Your laptop see's the router, but the problem lies between the router and the modem.
Try the following tasks in order: 1) Unplug the power to the router 2) Unplug the power to the modem (the black box that the router is networked to) 3) Wait 10 seconds. 4) Plug the power back into the modem 5) Plug the power back into the router.
This should solve the problem! If this was helpful then please give me a good rating, thanks!

This indicates that router can't detect cable modem or this is unresponsive, probably your modem is logically tied with your PC (MAC address associated), that's why when you connect them directly work fine, if this is the case, you'll have to clone the MAC address of your PC into your router, this should be at Setup Menu, Manage MAC addresses option.

There is a great article at Working with Windows Wireless Networks
If you need more help post back! Thumbs and testimonial are welcome!

Try powering down everything (pc, router, modem), for a few minutes (unplug the router and modem). The power back up again and try re-establishing a connection.
If that doesn't work ask for a paid expert or try your ISP
Good luck

I would contact your internet service provider. There is likely something wrong with your line that is causing your router to loose signal. I don't know what type of router you have, but a loss of signal usually causes that. There are other reasons, such as, your modem is going bad, your cable from the modem to the router has an internal break in a wire, your router could be going bad as well. Try power cycling both your model and router. You can do this by unplugging them for a couple of minutes and them plugging them back in. Plug in the modem first and wait a few minutes, then plug in your router and wait a few minutes, then try getting on-line. If this is a persistent issue even after doing all of this and contacting your ISP, then I would conclude that your hardware (modem, router, &\or ethernet cables) is giving out on you.

Router might not be set up with the modem. Your router broadcast wireless signal when it is powered on, so even if it is not connected to a modem(where you get your internet from)you will have a local connection. That's normal. You need to set up the router. Call linksys technical support, if they cannot help try http://technicalsupport.blog.friendster.com

i've never worked with a 7740, but i've installed hundreds of hn7000's and hn9000's. the issue is usually that the router and modem are defaulting to the same ip address. if your router supports has a web-based config utility (as most do) try cat-5'ing to the router with your computer while the router is NOT connected to the modem. log into the router and set it's ip address to something OTHER THAN 192.168.0.1 (i use 192.168.1.1 for my customers) reboot the router and reconnect it to the modem. the ip conflict should now be resolved.

Modem light goes RED if No external Ethernet device has been attached and detected OR The Ethernet link is down.
in your case it is going to be the DSL MODEM ....

Second cause could be The WAN interface has been disabled by the firmware.

TO enable it log on to your router's address http://192.168.10.1.

and look for WAN options.

http://broadband.custhelp.com/cgi-bin/broadband.cfg/php/enduser/std_adp.php?p_faqid=17058&p_sid=rTOCxT5j&p_lva=17178&p_accessibility=&p_redirect=&p_sp=cF9zcmNoPTEmcF9zb3J0X2J5PSZwX2dyaWRzb3J0PSZwX3Jvd19jbnQ9ODAsODAmcF9wcm9kcz02MzAsNjQ0JnBfY2F0cz0mcF9wdj0yLjY0NCZwX2N2PSZwX3BhZ2U9MQ%2A%2A&p_li=

Thanks ,, please let me now it worked or not

first check your computers internet connection settings.and also check for any updates that could pretain to your modem/or computer.the problem is with your main computer,and not with the router.second check your firewall,make sure the correct port is open to let the traffic in.