DSL > Asterisk > W/ existing DSL # ?

Discussion in 'VOIP' started by David Wiltkins, May 11, 2004.

  1. Is this possible?

    If my phone can detect an incoming call, why can't my Asterisk box do the
    same with a connection into my ethernet port? Does a simple inexpensive
    device exist that can translate incoming calls through my DSL line, to my
    ethernet port, to Asterisk?

    My goal is to send and receive soft calls through my PC, use my existing #,
    and accept multiple calls.

    Is this possible with Asterisk and a DSL line?

    Thank you
    David Wiltkins, May 11, 2004
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  2. David Wiltkins

    Mats K Guest


    You havn't descibed your system well but as a generic answer, YES asterisk
    can do that but...

    It depend on firewall configuration, asterisk configuration and you havn't
    describe that !

    Mats K, May 12, 2004
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  3. Ok, just getting started with pbx etc.. it's a little overwhelming, all
    sorts of new acronyms.

    I'm running Red Hat 9 and one of the RPM's for Asterisk from voip-info.org.
    I am not running a traditional firewall, just a Linksys router. Asterisk
    seemed to fire up fine after installing.

    In the quick start guide at voip-info.org, it was recommended that I bypass
    my router and connect my RH9 box directly to my DSL modem. After that, it
    said to copy the default settings from one of the config files for my PHONE
    and then call it's extension (default 1000).. I don't have a phone though. I
    prefer to run everything over ethernet from my Asterisk server to PC and
    make and recieve software calls only. This way I can integrate my existing
    front end gui with asterisk.

    I could not find any resources for this particular setup.

    Any suggestions or pointers would be greatly appreciated!

    David Wiltkins, May 12, 2004
  4. David Wiltkins

    Soren Rathje Guest

    Er... If I'm correct in understanding your request then it can not be

    You need to terminate your DSL in a filter in order for * to access your
    phone line...

    Minimum requirements for your set-up will then be...

    -- DSL modem -- ethernet
    -- DSL -- filter <
    -- Phone line -- POTS

    The POTS device can be one of the following:

    The low cost Wildcard X100P is interchangeable with a Intel 537
    (AMI-IA92 / AMI-IE92) Winmodem based card and should be available for
    around $25 + $30 however this is an old card and the TDM400P is the
    latest technology expandable to 4 lines (FXO or FXS).

    Regarding the FireWall... I've got my * server behind a FireWall with no
    problems, connecting to it with a soft/hard phone from the outside and
    peering with FWD with no problems also. All you need to know is what UDP
    ports go where and make the necessary adjustments in your NAT/FireWall
    settings and in the SIP.CONF..

    .... sip.conf ...

    .... rtp.conf ...

    From the above I have rules mapping UDP port 5060 and ports 10000-2000
    to the internal IP address of my * server (

    I would recommend that you check out the latest version from CVS since
    it contains substantial enhancements for services like VoiceMail and

    Anyway, all you ever wanted to know about * can be found here...

    -- Soren
    Soren Rathje, May 13, 2004
  5. Thanks for the reply. I'm getting more and more confused the more I read
    about this. Are you saying that my machine cannot "listen" for a phone call
    connect either directly to my linksys router OR connected directly to my DSL

    If you could please bare with and answer the following questions I'd be
    really grateful.

    1) Is it possible to call my existing DSL phone number (issued by the phone
    company) and have Asterisk answer? Or do I need to go through a third-party

    2) Is it possible for me to call anybody, anywhere in the US or do I need to
    go through a service?

    3) Can my single line accept multiple calls even if I'm on the phone? As in
    I'm talking to someone, another one calls and is put into voice mail, and
    then another one calls and is put into voice mail etc.. What happens if 10
    people call at once? Can Asterisk queue all 10 calls until I can transfer
    over to them?

    4) I was a little thrown off by your diagram. You mentioned your Asterisk
    machine is behind a firewall, but your using a filter.. is this what you

    DSL line > DSL modem > router/firewall > asterisk box
    DSL line > Filter ------phone line----------wildcard etc > asterisk box

    Any clarification would be greatly appreciated.
    David Wiltkins, May 13, 2004
  6. Which DSL-phone number??? You just get a IP ...
    You can call any VoIP-phone, but for POTS you need a service for
    That's just a question of your bandwith. Calculate 20 KBit/s for G.729
    and 160 KBit/s for G.711.
    I think you confused each other. I assume filter means splitter (a
    little box which separates the frequencys for POTS and DSL into two

    is this your setup?

    ----> POTS (PlainOldTelephoneSystem)
    Copper-Line ---> Splitter
    ----> DSL-Modem ----> Router ----> Asterisk-box

    The VoIP-docs mean that you directly connect your broadband modem to
    the network card in your * box and use use the * box as router. But it
    should also work with you hardware router by using port-mapping.

    By the way, if it's a Linksys WRT-54G you can get the GPL'ed
    Linux-firmware. There's even a slim Debian distribution available. The
    router should be to weak, but it would be great If one could install
    Asterisk directly on the router ;-)

    Juhura Nagamichi, May 13, 2004
  7. David Wiltkins

    John Sutter Guest

    By DSL phone number, you mean the phone number of the analog phone line
    upon wich DSL is running? You will need an FXO device connected to the
    filtered analog phone line. The easiest way to get an FXO is to buy a
    card like:
    from Digium. This card also has an FXS to connect to a hard phone. This
    is a good idea to have anyways. On my system at home, I always have the
    house line connected to an FXS device and my analog line to the FXO card.
    I also have a bypass switch in case I really botch things or we lose power.

    You do not need special service for the single line. You can contract with
    iconnecthere.com (and others) to get a new phone number (about $9/mo) that
    will be send calls directly to your asterisk box. I doubt there is any number
    portability available. This might be a way to be able to accept multiple phone
    calls, though they might limit that ability to business customers. That and
    your DSL connection probably does not have enough uplink bandwidth to support
    more than one or maybe two calls (unless you use G.729 or something like that).

    For analog calls though, 1 line, 1 call in or out.

    You can call anyone on FreeWorldDial for free. If your friends have asterisk
    systems or have softphones and their firewalls set up properly, you can make
    them extensions of your system (or you of theirs..). Beyond that, you need a
    service such as iconnecthere.com or nuphone.com. I use these two for US, local
    long distance, and international calling.

    No. You either need an expensive, high capacity T1/PRI line or multiple
    analog phone lines.
    The filter is used to prevent all the DSL signals from getting to the phone.
    It's usually a little box sitting outside the house or you might have one
    for every phone in your house. It's not a filter in the firewall/router

    -- John
    John Sutter, May 13, 2004
  8. David Wiltkins

    Mats K Guest

    What do you mean with DSL phone ?

    Is this a analogue telephone or an IP telephone ?
    Maybee you could post a url to the DSL providers product page and maybee you
    could tell us what type of DSL phone you have.

    But to clarify a bit, no 3rd parties ar needed if there is an analogue or IP
    telephone we are talking about.
    If it's an analogue telephone then you have to buy a card to the PC with
    If it's an IP telephone then you just have to configure asterisk to talk to
    that provider, there are several examples on "Free World Dialup"
    configurations that you should be able to follow.

    NO you don't need a service if its an analogue telephone or a IP telephone
    service that asterisk can interface with.

    It depends.
    The filter is a physical box where the cable is split into a DSL connection
    and a telephone connection. The method used is that the telephone connection
    uses one frequency range and the DSL uses another on the same physical
    cable, so you can say they share the cable !

    Oh by the way the analogue telephone could be a ISDN telephone as well but
    from what I know havn't ISDN penetrated the USA market in a significant way.

    So as I have said earlier as mutch details as possible avoids a lot of
    confusion, questions and speculations !

    Kind regards
    Mats K, May 13, 2004
  9. David Wiltkins

    Soren Rathje Guest

    If you have a phone number where you can connect a physical (or soft)
    phone - YES, Asterisk can handle the call with the proper interface.

    You will most likely need a service somewhere to terminate your calls on
    regular phone lines if that is what you want.

    PSTN - NO. Any call waiting, voicemail on your phone number is handled
    by your PTT and is not even getting close to your set of wires if you
    are busy on the phone.

    ISDN - YES. ISDN will provide from 2 (BRI) to 30 (PRI) lines that can be
    handled by Asterisk in the way you describe.

    YES, the filter is for me to split DSL and PSTN into two sets of cables.

    -- Soren
    Soren Rathje, May 14, 2004
  10. David Wiltkins

    John Sutter Guest

    Now I'm getting confused. I didn't think that it was possible to have DSL
    over an ISDN line. Have I been missing out?

    -- John
    John Sutter, May 14, 2004
  11. David Wiltkins

    Mats K Guest

    Yes it's possible to share the same cable for both ISDN and DSL.

    Mats K, May 14, 2004
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