Thread: Wireless Router to ZTE ZXDSL 831AII modem

Hello. I have got a BSNL broadband connection here in Umargam, Gujarat. They have given a ZTE modem. I connected this to my laptop (IP was 192.168.0.2 and I changed to IP 192.168.1.2) and configured as instructed. I only had to connect PPPoE and give my user name and password and it started. On my laptop, I put 192.168.1.1 as the gateway. Now I want to connect a Wireless router (IP 192.168.0.11) in between as I have number of computers connected through switches (IP 192.168.0.2 to 192.168.0.10). All have subnet 255.255.255.0. How do I make the changes in the modem and router? Is there any way to backup the ZTE modem settings?

Every router will have an option to backup the router settings to disk. The file is usually saved as .cfg. Check if there is a Tools menu or equivalent. It will be available. I do not have the guide so I cannot tell exactly.

If ZTE ZXDSL 831AII is already a wireless modem, why do you want to add another wireless router to the circuit? You can simply increase the DHCP range in the ZTE router to accomodate as many machines as you like.

However, that does not mean that you cannot add another router in the circuit. Sometimes this is good because you can create two different networks that way and it offers some advantages such as:

a) The second network can be completely protected from internet access and can be made to work as an internal network only.
b) The second wireless router when strategically placed can extend the wireless network coverage.

To add the second router to the network, it must be in a different subnet. For example, if your ZTE router's IP address is 192.168.1.2 then the new wireless router's internal IP address could be 192.168.2.1. In fact the new router's ip address can be anything other than from the range 192.168.1.0 to 192.168.1.255.

One more question. Why are you assigning manual IP addresses to your desktops and laptops? My advise is to leave them to automatic. The DHCP in the router will then assign automatic IP addresses to all connected machines. The only exception is networked printers. Read this thread: http://www.indiabroadband.net/comput...vironment.html (How to setup a networked printer in SOHO environment).

Finally (and probably you know it yourselves), you can connect any number of machines as you like to your network but the ISP bandwidth will be shared by all.

hello, thanks for the reply. this is my office network and i thought it was better to have a static ip. I am then able to restrict the use of net to limited machines (using ip security) through my router. the bsnl modem is not wireless. i want to keep my wireless router for restricting the net to limited ip's and also access from my laptop through wireless.
i also had a small network of 3 machines at home in which there was an access point for wireless. today i added the bsnl modem here and i could get it working. i disabled dchp on the adsl modem and just put the gateway as 192.168.1.1 in the AP and my computers. so i think i will be able to do the same in my office network. will try though. hope i have not confused things more.
suppose the adsl modem is 192.168.1.1:255.255.255.0 and my machines are all 192.168.1.x:255.255.255.0, can my wireless router also not be in same range? if not then can i just put the ip address of router as say 192.168.2.1:255.255.255.0 and put gateway as 192.168.1.1? In this case should my computers be in range 192.168.1.x or 192.168.2.x? Or do I have to use router as bridge and put PPPoE in router. i am not very confident of doing this correctly.

When you put a router in any network (public or private) it has an external IP address and an internal IP address.

The external IP address is given the DHCP service from the source network. For example in case of BSNL ADSL modem/router, the BSNL server's DHCP gives it an address like 117.x.x.x. The internal address of the same router is 192.168.1.1. The NAT services inside the router is able to translate this external and internal IP address.

When your PC is connected to the router, the gateway address is 192.168.1.1 (the router).

Now you want to add another router in this network. In this case the DHCP service of the BSNL router will provide the external IP address. This could be something like 192.168.1.5. Now you need to assign an internal IP to this router. It cannot be any address like 192.168.1.x because it conflicts with the DHCP address range of the BSNL router..

Finally the bridge or PPPoE question. You should configure your BSNL router in bridge mode and wireless router in PPPoE mode. This way anyone connected to your BSNL router's network will not be able to connect to internet because the wireless router has blocked it's internet bridge. All those machines that are connected to wireless router (in PPPoE mode) will be able to connect to internet. If you configure WPA-PSK security no one will be able to connect to the wireless router unless you provide the WPA key. And you should also change the BSNL password.

HTH. Any more queries and I will be glad to answer.

hi, thanks for the explanation. it made me understand the difference in ip address and i could setup the Linksys router in my network without bridging the BSNL modem. here is what i did.
1) Modem LAN IP as 192.168.1.1. DCHP is off. PPPoE name and password entered and connected to internet.
2) Wireless Router after Modem, connected to WAN PORT. Router WAN IP is 192.168.1.2 and LAN IP is 192.168.0.1. Gateway in router is 192.168.1.1
3) Computers on my network are with IP 192.168.0.x and gateway is 192.168.0.1.

Net is working fine and I am able to use the IP address filtering in my router to restrict internet access.
Would bridging have given any benefit? It seems it is not possible to do the bridging option directly in the ZTE 831 modem. Also this modem does not have any backup option, I couldnt find it.

Thanks for the help, really appreciate it.

Every ADSL modem/router or a plain wired/wireless router has bridge option as well as PPPoE. Your ZTE modem will have it also.

When there are two routers on the same network, the following configuration options are available:

a) Both in bridge mode. This offers no advantage and besides in bridge mode only one computer can connect directly to internet. Other computers can connect to the internet through the first computer (shared internet connection).

b) One router as bridge; other in PPPoE.

It is not possible to connect both in PPPoE simply because only one dialing is possible.

My personal preference is BSNL provided modem in PPPoE mode and Wireless router in bridge mode. There is no particular advantage; just my preference.

But it all depends upon router features. BSNL provides ADSL modem/routers which have a firmware that has stripped down features. For example, BSNL's new UT-300R2U modems does not provide the 'Virtual Server' option so useful for controlled port forwarding. It provides the NAT-DMZ instead which opens all the ports.

I have written quite a few articles on broadband. These are:

1. http://www.indiabroadband.net/comput...ty-primer.html
2. http://www.indiabroadband.net/bsnl-b...primer-ii.html
3. http://www.indiabroadband.net/bsnl-b...and-guide.html (The very basic Broadband Guide)
4. http://www.indiabroadband.net/bsnl-b...er-wrt54g.html (Setup of ADSL Modem/Router UT-300R2U with Linksys Wireless Router WRT54G)
5. http://www.indiabroadband.net/bsnl-b...onnection.html (Solution for multiple machines connecting to same BB connection)
6. http://www.indiabroadband.net/bsnl-b...ing-guide.html (Torrents and Port Forwarding Guide)
7. http://www.indiabroadband.net/bsnl-b...-wgr614v7.html (Setup of UT-300R2 with Netgear WGR614v7)
8. http://www.indiabroadband.net/comput...vironment.html (How to setup a networked printer in SOHO environment)

I do claim to have scripted anything new. Rather the articles are a collection of my own experiences, various posts/blogs on the net and some (shameless) 'borrowing' from Wikipedia (my favourite site). What I have tried to do is collate them at one place. Hope that they will help you.

Wow, thats quite a list. I will try to do some reading. so do you think what i have set up is ok or does it require changes for something better.
i also have another question. we have an epabx in the office and what we have done is we have taken a parallel direct line to connect to the adsl modem. this is giving some disturbance in the telephone line and also when telephone is going on, we dont get the net connection. does this means i have to use the splitter given by bsnl?

Originally Posted by hemang

Wow, thats quite a list. I will try to do some reading. so do you think what i have set up is ok or does it require changes for something better.
i also have another question. we have an epabx in the office and what we have done is we have taken a parallel direct line to connect to the adsl modem. this is giving some disturbance in the telephone line and also when telephone is going on, we dont get the net connection. does this means i have to use the splitter given by bsnl?

You are well advised to use a splitter. The spliiter should be installed at the very first (entry) point of the telephone connection. The ADSL part of the splitter should directly go to the ADSL modem and the phone connection should run to the EPABX.

One of my articles in the above list deals with this problem.

hy Guys ! will you please tell me know where i can download ZTE ZXDSL 831AII modem circuit sheet or circuit diagram ! please

(1)Confirm the modem is out of order, and you want to open the unit and carry out repairs using a schematic diagram, and a manual with parts IC's etc listed with Part number.
(2) can you access the menu pages ?

feedback.

yeah ! Actually i got some problem with Power supply and it needs to be repaired ! will you please let me know the circuit !

Give details of the Power adapter used : Voltage AC or DC output
If you have a Digital mutimeter , measure the output Off load.

Which leds are not glowing ?
confirm menu pages appeared as in this document.

Guide; one version.
http://www.sltnet.lk/adsl_pdf/ZXDSL_831_II.pdf

Dear Sir

i think you are not getting me as 5.6v adapter comes with modem provided by bsnl. i accidentally connected 12 volt adapter that caused the damage to the circuit. Now i want to repair the circuit ! hope you got it so i need the circuit of the modem ! thanks

Forum Tip
Use short quote as given below:
and answer specific point/query raised by members.
Then add adddition comments ask further questions.

i think you are not getting me as 5.6v adapter comes with modem provided by bsnl. i accidentally connected 12 volt adapter that caused the damage to the circuit

Now only you are explaining how you suspect the damage to the modem, after I raised query about the adapter.

Option 1:
Send PM (Private message) to @mvs sarma and request the details you are looking for. He has done repairs to many modems.
No where a schematic diagram or maintenance manual is available for the modem in the web. including ZTE web site.

Option 2:
Open the unit and see whether (a)a fuse is blown if provided internally, ( very unlikely)
(a) look for burnt /blown out Electrolytic condenser .
(b) Note the number of any IC'/Transistor regulator etc in the power chain.
(c) Probable required voltage could be about 3.3V D.C for the ICs and transistors and Leds with series resistors etc.

Dear Sir

I don't suspect but am sure there is a fault in power supply or something else because when i switch the power on no red light or lamps shows the light as it used to be. And thanks as i was expecting a circuit but !!!!!!!!!!!!

Previous post edited. Understand no LED is glowing.
Please Give feedback when you get response from @ mvs sarma.
He may ask details , I specified , to decide whether modem
can be salvaged or not.

Future ref : LEDs condition etc.
http://mp.bsnl.co.in/bb/zte/zte831.htm

Dear Sir

No LED light glows after switching on the modem as i know when i connect it to 12v A.c the damaged was done !

Modem needing DC input with proper polarity will not have
rectifier circuit inside.
Modem with A.C ~ input will have a rectifier circuit (usually Bridge)
Excess voltage will damage in either case.


Your modem is DEAD! You can open and do "post mortem"