RJ45 Modem RJ11 router. How to connect?

Posted on 2008-10-30
Last Modified: 2013-12-14
I have this ADSL router and I want to connect it on my ISPs modem, so that I can have wireless connectivity.

The problem is that the WAN port on this router is an RJ11 port, and from my ISPs modem I can only have RJ45 (Ethernet) output. I understand that this router is mean to replace the ISPs modem, but unfortunately I cannot do that.

So in order to use the wireless functionality of this router I must find a way to connect to my ISPs modem.

Is there a way to do that?

Question by:AJKBOC
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Expert Comment

ID: 22848785
Sadly not.

The signal that RJ11 tries to recive and that RJ45 (ethernet) are completely different.

Your wireless modem will be attempting to connect by sending User & Pass requests via your hacked up RJ11 to 45 connector, meaning that it will fail in the most epic way.

As horrible as it is your best off getting a Wireless access point. Netgear or Dlink are reccomended but it's personal choice.

Sorry I couldn't be of more help, and good luck!
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Expert Comment

ID: 22854791
What kind of modem is it from your ISP?

And which version of the P-660HW do you have, exactly?
ZyXEL has made 10 different variations of the P-660HW.
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Expert Comment

ID: 22854809
Oh, and it appears all 10 variations have included a 4-port switch, so just turn off the DHCP server in the ZyXEL, connect a cat5 cable from the modem to one of those 4 LAN switch ports, and - voila - you have an access point instead of a router... use the other 3 ports to connect wired devices to the internet through the modem, if desired.
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Expert Comment

by:Rob Williams
ID: 22858816
To add to DAR247's comments:
If you wish to share resources between the wired and wireless LAN consider putting them on the same subnet. To do so you need to make the Zyxel an access point, rather than a gateway. To do so:
-no changes required to the existing modem
-reset the Zyxel WAN connection to default, i.e un-configured
-assign the Zyxel LAN side an IP address in the same subnet as the modem's LAN.  Make sure it does not conflict with the modems's DHCP range, or any statically assigned devices
-disable DHCP on the Zyxel
-wireless connections should be configured in the normal manor
-connect a cable from one of the LAN ports of your switch or LAn port of the modem to one of the LAN ports of the Zyxel. If the lights do not light up indicating a connection you may need a cross-over cable (usually only necessary on older units)
-now all devices should have Internet access and be able to easily connect to one another to share resources. Don't forget to refresh and DHCP addresses on the wireless clients  
LVL 44

Expert Comment

ID: 22860340
Well, the IP address assigned to the ZyXEL does not determine what network the wired devices are on. They will be assigned an IP from the modem's DHCP server, the same as the wireless devices are, and they will all be in the same network... usually, modems don't support assigning more than 32 addresses, though.

All the IP address on the ZyXEL's LAN interface does is facilitate access to the web configuration menu of the ZyXEL. Other than that it's just a dumb (i.e. unmanaged) switch.
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Expert Comment

by:Rob Williams
ID: 22861257
>>"Well, the IP address assigned to the ZyXEL does not determine what network the wired devices are on."
Was this directed at my comments above Darr247. If so, correct, that is why the ZyXEL needs to be manually assigned an IP in the same subnet as the modem, as stated.

>>"All the IP address on the ZyXEL's LAN interface does is facilitate access to the web configuration menu of the ZyXEL"
Correct but you need that to manage the unit and configure the wireless access. If in a different subnet you will not be able to access it.

Expert Comment

ID: 22865926
You would need to purchase a RJ11 to RJ45 converter, try shiopping around teh local store or maybe you can buy from 

Expert Comment

ID: 22884955
Use the ZyXEL DSL router in leui of the supplied ISP DSL modem.  Be sure to use the correct VPI/VCI settings in the ZyXEL...

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Expert Comment

ID: 22886155
The original question stated that could not be done, P2E.
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Accepted Solution

Darr247 earned 500 total points
ID: 23003214
I have many times connected from the modem to one of the the LAN ports on a 4-port router and used it as an access point and switch, so obviously you did NOT try everything or you would have discovered that setup works just as you asked.

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