WRT54GS and analog phone

Discussion in 'Linksys Official Firmware' started by Robbby, Mar 13, 2006.

  1. Robbby

    Robbby Network Guru Member

    i have got a WRT54GS, i d like if possible connect an analog phone to 1 rj45 port (the analog phone has rj11, so i dunno if this is possible) and than i d like to run asterisk on it and implement a voip(sip) solution using 1 account for receiving and 1 for calling, is this dream possible or i have to buy an ata adapter?
  2. t4thfavor

    t4thfavor Network Guru Member

    dont you need a voip adapter for that?
  3. Robbby

    Robbby Network Guru Member

    that is waht i d like to avoid, i think the only problem could be the rj11 fit in rj45 connector (phisically is ok but will it work?) thatn i think installing and configuring the asterisk could work
    any idea?
  4. t4thfavor

    t4thfavor Network Guru Member

    i have been around for a while here and never heard of it happening. Not that it is impossible.

    Why don't you want to use a voip adapter?
    A just because you don't.
    B you have a good reason such as ...
  5. Robbby

    Robbby Network Guru Member

    the reasons are :
    1) i d like to have all in one box so no other adapters
    2) cost, i know it is cheap an adapter but than a voipphone has the same price of an adapter
    3) if have to spend money for such solution i d prefer get an old handled with wifi future run a client on it and use it as wifi phone
  6. t4thfavor

    t4thfavor Network Guru Member

    you can get an adapter for free when you sign up for most voip providers.

    also if you mangle the phone and then decide to buy another phone you have to mangle the new one as well.

    With the VOIP adapter you can put it into your router via cat5 and then hardwire it into your house phone line. which is what I have done. This means when you plug a phone into an existing jack in the house it will automatically use the voip phone. and you will never have to buy a special VOIP phone. you just continue using the phones that you already have. I guess if you really have to have the all in one solution and are good at coding C++ you can set one of the rj45 jacks to run sip (has to be coded in) then replace the rj11 jack on the phone with an rj45 make the 4 phone wires go to the right pins on the rj45 and then pray for the router gods to smile upon you. What you are trying to accomplish is (probably) possible but totally impractical. you will have more headaches than the 40 bucks the VOIP adapter would cost you to buy. And in the end it probably wont work.

    someone who can probably give you insight to this situation would be located at www.dd-wrt.com and his name would be brainslayer. now he might not help. He is just someone who can code the firmware for you if he feels like it.
  7. NateHoy

    NateHoy Network Guru Member

    I seriously, SERIOUSLY doubt an Ethernet RJ45 port, that feeds 5vdc (if I recall correctly) digital signalling can be converted to anything resembling a ~48V analog RJ11 connection.

    Can the plug fit? Sure. You can jam an RJ11 cable into an RJ45 port. The 2 or 4 pins in the RJ11 cable will even connect. Most RJ11 cables will expect to use the middle pins (2-3 for RJ11, pins 4-5 in RJ45 nomenclature). But the Ethernet Spec calls for signalling on 1, 2, 3, and 6. So you can't use a standard RJ11 cable. Let's assume you've lashed up an RJ45->RJ11 cable by moving a couple of pins (1-2, say) on the RJ45 to pins 2-3 of the RJ11, so you have physical voltage.

    But in order to get a VoIP line in there, you will need to feed an distinct signal to one of the RJ45 ports, requiring a really refined level of control over that single port that I don't even think the hardware allows for, much less the stock firmware. But let's assume that is possible.

    Now, step up the voltage by a factor of 10. RJ45 calls for voltages under 5vdc. Analog telephony uses 48V. You aren't going to find a setting like that in firmware.

    Oh, yeah, then you need a DAC (Digital to Analog Converter). put inline somewhere, to actually turn the Ethernet packets into an analog signal. Assuming you have refined enough control over the signal on the RJ45 jack, which you don't, you could do that in firmware by writing a software DAC and compiling it into a Linux kernel that is already pushed for space, but then the 200mhz processor as found in the WRT54G series routers isn't going to be nearly powerful enough to process a 64kbps G.711 VoIP data stream AND do any routing of any sort.

    So, after performing one easy task (customized Rj45->RJ11 cable), you only have three impossible things to do after that. ;)
  8. NateHoy

    NateHoy Network Guru Member

    Oh, I just caught the last part of your note - that you also wanted to load Asterisk on the WRT54G...

    I love the idea, bro, but you're looking at some SERIOUS horsepower to run just Asterisk. Like, more memory and processor than the WRT54G ever dreamed of having.

    You may want to look into just installing an Asterisk or other VoIP switching PC, and putting two Ethernet adapters in it and seeing if you can get IPCop, M0n0wall, or Smoothwall running on it so it can double as a router. You could probably get clever modding a case to hold a simple Ethernet switch so the ports come out of the side or something so it could be all in one box, and you could probably even do it with some pretty small motherboards and cases.

    But a WRT54G is going to need EXTENSIVE hardware modifications to even begin to touch what you are looking at. Cheaper to just get a VoIP adapter and call it a day.
  9. Robbby

    Robbby Network Guru Member

    well ok you all convinced me it was just a dream, so i ll go for the adapter, just last question is it possible to configure the adapter for the outgoing call with a provider and for the incoming call with anotherone?
  10. NateHoy

    NateHoy Network Guru Member

    Depends on the adapter. I would assume that most of them can handle multiple SIP servers, though it may be necessary to use different phone ports for that ("Line 1" for incoming, "Line 2" for outgoing), etc.

    You'll have to look into that for whatever device you choose.
  11. EnigmaX

    EnigmaX Guest


    Well after struggling to unlock my RTP300 from Vonage I can login to admin
    but cannot change the firmware because I don't have enough rights.

    I melted my WRT54G because I've flashed it too many times and bricked
    it till I get a jTag cable. I went on flebay and purchased/bid on bunch of
    routers and ended up with 3 WRT54G.

    Can't I just flash one or two WRT54G with DD-WRT and after purchase
    a VoIP Phone and plug it directly in. I don't mind buying one of them fancy
    multi-line VoIP phones to have in bedroom and livingroom.

    I also downloaded TrixBox and I have a spare computer with dual ethernet
    but that might be an overkill of what I want, I still need to dump another 300
    or so on some special card.

    Any decent/not too expensive VoIP phone suggestions to work with WRT54G
    would be appreciated.
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