Netgear WNR3500Lv2 + asterisk + usb phone =will it work?


I am very new here… I tried to solve my idea/problem on 2 forums but nobody could help me, that is why I am asking here.
I am trying to get some info for several days (weeks?) if my idea should work…

I am planing to but WNR3500L v2 router with 480mHz proc and 128mb ram with an usb port.
I know that I can install asterisk on it (the router fully supports tomato firmware)

My 1st question is - will I be able to plug a softphone usb into usb port on my router and will it work? I would like to have a softphone working 24/7 working and a router would be a great think to connect it as it is plugged to the internet 24/7 (a laptop or other computer works only a couple of hours a day - I know that it would be easier to work but I would like to try to plug to router - if possible of course).

I know about IP phones which you can plut to rj45 port in router but this is not what I am looking for… I just wonder if the router could be a ‘soft IP gate’ for a usb phone

My 2nd question: Is there a posibility to connect a standard analogue telephone with rj11 socked to a rj45 port in the router and to ‘tell’ installed asterisk on this router that eg LAN port 3 (rs45) where I plugged analogue telephone with a rj11 to rj45 converter that it should communicate to each other? I know that rj11 have to wires and rj45 has got min. 4 wires… what about the power? rj11 gives power to telephone as well as far as I know?

I found sth like that but I do not really know if this is what I am looking for: … G_4967.jpg
and … sys+WRT54G


many thanks for even smalles reply,

…nobody knows if it is possible? any idea? please give me any direction… link where could I reas sth about it, please!


The question requires detailed knowledge of the router hardware capabilites. That knowledge will be in limited supply amongst the dozen or so regulars here.

A USB soft phone will, realistically, require you to run a SIP soft phone on the device, as well, as I’m not aware of USB soft phones that look like ethernet adapters, and Asterisk’s direct sound card support is not really suitable for production use.

If this is a simple router, the RJ45 connectors will be totally incompatible with analogue telephones. It is just about conceivable that an ADSL port might be programmable to handle analogue phones, but I doubt that you could make it source normal or ringing voltages, or generate loop signalling. I’d also suspect that they normally contain high pass filters to reject baseband audio.

0.48Hz is way too slow, and I don’t know how you construct a memory containing less than one bit! If you meant 128 Mega Bytes, rather than milli-bits, I haven’t tried Asterisk on anything that small. It is generally fairly profligate with memory, but it might support a very small system on that. A 350MHz PC on a high end motherboard can support at least one line with Asterisk. I’m not sure about RISC systems, if this is one of those.

This question should have been on Asterisk Support, if on an Asterisk forum, although it is probably better directed to a WNR3500 hackers forum.

hello david55,

Thanks for your reply.

I know some base spec regarding the router… I made a misteake in my first post.

The WNR 3500l V2 has got:
Five (5) (1 WAN, 4 LAN) Gigabit Ethernet ports
480 MHz powerful MIPS 74K processor
Memory: 128 MB NAND flash and 128 MB RAM
USB port

it does support alternative firmware like TOMATO
I found Asterisk compilations which are supported by tomato optware:

soft phone:
you said that [quote] A USB soft phone will, realistically, require you to run a SIP soft phone on the device [/quote].
Asterisk is a SIP client isn’t it? alternativly any linux based SIP client should work (tomato is a linux distribution in some sort I think?) I do not know what with the sound card? It should be then soft modulated by the MIPS 74K processor?

It is not an ADSL router (modem + router) it is a pure router just with rj45 connectors and an USB port… I asked previously about connecting rj11 into the rj45 because I found a converter on ebay: … 500wt_1156
or this one: … 377wt_1352

I hope this info will help better to understand my problem/idea :smile:

PS I did not know which subformu would suit best to this subject if you could move the topic to a better one please do this.
PS2. I already asked this subect to a forum but nobody answer it yet


USB phones normally look like USB sound cards to the PC. A SIP phone looks like an ethernet device.

The RJ45 adapter is only an electrical connection between certain pins. It has no intelligence.


a SIP phone = VoIP phone then? like Siemens 470IP I understand - it can be plugged to any router with rs45 port… so this option does not interest me… it cost a lot of money :wink:

so USB phone is the thing I would like to connect to the router… to it’s USB port right? I thought that a usb phone is just a numpad + speaker + microphone but without a sound card… I thought that computer do the work with the sound encoding?

No the USB device contains the A/D and D/A converter.

From Asterisk’s point of view, it is a sound card, and Asterisk’s support of sound cards is only really good for basic demonstrations and paging.

ok, so I know now more and more :smile:

It can be said then that you think that plugging a usb phone is possible to a router with installed Asterisk but the voice (audio) quality will be poor?

It is beacuse of codecs installed in Asterisk? eg there is no high quality audio codecs as G.722 etc?


Asterisk doesn’t have the echo cancellation and possibly not the high quality jitter buffer logic to support its being an IP phone itself.

It also doesn’t have USB Human Interface Device support for the phone keypad.

ok ok but nos so fast please ; )

  1. “echo cancellation issue” means that even if nobody say something there might be some noise going form the usb phone speaker?

  2. “not the high quality jitter buffer logic” means that the voip calls might be hard to undarstand (noises/scatters)?

in other hands would you advancea thesis that I shouldn’t even try to install asterisk on this router + buy a USB softphone and connect it the router at any way


to try to install other linux SIP client on the router and try it with usb phone? would you reccomend any if it is possible in your opinion?

many thanks for your help

so ther should be: Asterisk, then a SIP softphone software on the router with usb device support and then conected usb phone to the usb port on router?

When the other end is talking, their speech will go out of the speaker on the USB phone and some will be picked up by the microphone. With a short delay one doesn’t notice this. With VoIP type delays, it can be exceedingly annoying, so the phone should, adaptively, predict how much will be returned, and with what delay, and subtract it out.

The suitability of the hardware depends on what you want to achieve!

hello again,

I was reading again about it…

it looks that the best option for me should be:

  1. wnr3500l v2 + tomato onboard (with it I will be able to install on the router additional software)
  2. now should be installed and configured eg. SER (SIP Express Router), a free SIP server
  3. to USB port on the router should be connected a USB phone

the only problem might be with USB Phone - as david55 noticed it is a USB sound card + USB microphone + USB speaker + USB numpad keybord allinone thing and this need to be detected by Tomato - probably additional audio drivers need to be installed to detect usb sound card on this system? Am I right?