Data over VoIP

Discussion in 'VOIP' started by Peter, Oct 16, 2003.

  1. Peter

    Peter Guest

    What would be a good choice for standalone 1-port FXO device with decent
    data-over-VoIP support? Something within couple of hundreds range. What is
    the data transmission rate I can possibly expect from such a setup?

    Peter
     
    Peter, Oct 16, 2003
    #1
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  2. Peter

    Ian Guest

    What are you on about?
     
    Ian, Oct 17, 2003
    #2
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  3. Peter

    Miguel Cruz Guest

    He wants to encapsulate data in VoIP traffic so he can establish a virtual
    modem connection and run Net2Phone on top of that, thereby cheating the
    system by getting a phone call for the price of a phone call.

    miguel
     
    Miguel Cruz, Oct 17, 2003
    #3
  4. Peter

    Peter Guest

    What are you on about?
    I like that... phone call for the price of a phone call ;) What I want is
    modem (dialup) connection routed via VoIP to lower costs. Yes, there are
    still a couple of applications requiring direct dialup connection.

    Peter
     
    Peter, Oct 17, 2003
    #4
  5. Peter

    SPD Guest

    "...connection routed via VoIP..." Are you trying to dial into an ISP,
    then have your data take the same path that the ISP has set aside
    for it's voice-over-IP traffic? If not please clarify because the
    way your stating this request doesn't make sense.

    Thanks,Steve
     
    SPD, Oct 17, 2003
    #5
  6. ~ What would be a good choice for standalone 1-port FXO device with decent
    ~ data-over-VoIP support? Something within couple of hundreds range. What is
    ~ the data transmission rate I can possibly expect from such a setup?
    ~
    ~ Peter
    ~

    To clarify: you want to run modem over VoIP?

    It is theoretically possible to achieve V.90 over VoIP
    (with G.711/G.Clear codecs, VAD off, shrunk-down jitter
    buffers, RTP redundancy in the network.)

    See http://www.cisco.com/en/US/products...s_feature_guide09186a00800b3568.html#xtocid17
    for some guidelines.

    Do you have control of the packet network? Or are you
    thinking of using a public VoIP network? In the latter
    case, you should talk to the network provider to find out
    what if anything they support.

    Aaron
     
    Aaron Leonard, Oct 17, 2003
    #6
  7. Peter

    SPD Guest

    Aaron:

    Other than a Fax environment when would you use such
    functionality? I'm curious how it could be used given that
    anyone with access to the VoIP environment probably
    already has a working IP connection over which to pass
    data.

    Thanks,Steve
     
    SPD, Oct 17, 2003
    #7
  8. Peter

    root Guest

    Encapsulating data in VoIP traffic is possible so that one can establish a
    virtual modem connection between two different VoIP points. However, I
    don't see the "cheating the system ..." scheme as you pointed out. Perhaps,
    you will need to clarify it.
     
    root, Oct 18, 2003
    #8
  9. Peter

    Miguel Cruz Guest

    I'm not sure you're going to have much luck doing that (too much D/A and
    A/D). If it does you'd have low data rates (I'd be impressed if you could
    get a 14.4 connection). Can't you use the underlying data transport that the
    VoIP is riding on?

    Since VoIP is a value-added service, it's almost sure that raw data will be
    cheaper for you to send anyway.

    miguel
     
    Miguel Cruz, Oct 18, 2003
    #9
  10. Peter

    Peter Guest

    "...connection routed via VoIP..." Are you trying to dial into an ISP,
    OK, I guess I need to go into a bit more detail on this. I have a specific
    application that requires it's own proprietary dial-out modem connection to
    work (don't tell me to dump it, this is not the issue here). To cut costs on
    the dial-out connection I'm looking to route it thru internet, i.e. the
    whole thing could look like this:

    client computer -> modem -> dialup into local gateway -> VoIP on public
    internet -> termination point into PSTN -> dialup into server computer

    OR

    client computer -> virtual modem connection over public internet ->
    termination point into PSTN -> dialup into server computer

    I'd be looking at either establishing termination point myself or utilizing
    services of existing VoIP provider.

    To complicate matters this is a mission-critical application, and
    reliability is key issue. There is software available that can do the second
    scheme, then it would require my own termination point (which is OK), but
    I'm not happy with the idea of using computer (especially Windows) for that.
    Too many things can go wrong.

    So far I haven't found any standalone hardware solutions that would do this,
    so VoIP boxes seem like the only alternative. Data transmission speed is not
    critical, and the added benefit of voice-over-IP could come in useful...

    Peter
     
    Peter, Oct 18, 2003
    #10
  11. Peter

    Ian Guest


    Why not use serial to IP converters. if what you want is a serial link
    over IP not VOIP. I have deployed many of these fo such things as
    securty system. As to putting data over IP as per the cisco way its
    very wastefull the ones I did meant we had to use a full 64K for a 33k
    link.

    Ian
     
    Ian, Oct 18, 2003
    #11
  12. OK, I guess I need to go into a bit more detail on this. I have a specific
    Makes sense. I still have an antique 2400 bps modem (configured to run
    at 1200) because that's what bank credit card auth terminals use, and
    it's much cheaper to pretend to be a terminal than to use something like
    Cybercash.
    Oh. then the answer is easy. Get a real phone line from your ILEC or
    a CLEC.

    I like my VoIP setup, but it's much more fragile than my phone line,
    even though my ILEC is my ISP and I have a T1, not consumer DSL. It's
    more sensitive to power failures, network route flaps, all of the
    stuff that makes net connections flaky. Also, the codecs in VoIP
    systems aren't designed to handle modem signals other than faxes, so I
    have my doubts about how well modem over VoIP would work even under
    the best of circumstances.
     
    John R. Levine, Oct 18, 2003
    #12
  13. Peter

    root Guest

    If you tell us exact application, perhaps it will become more clear and
    helpfull to help you. From your explanation, I assume you can setup a Linux
    machine at the source/termination points. On both ends, equipped the Linux
    machine with a modem each. If your application talks PPP, then setup the
    source point to accept PPP connection and have this device connected
    through PPP dial-in connection. Once connected, tell the device to remotely
    login (telnet) into the destination Linux machine. Then, use minicom to do
    the dial-out to a local server computer. This connection is much more
    efficient/faster than riding on top of VoIP. AFAIK, VoIP uses only about
    2KBps stream in each direction to send/receive compressed audio stream.
    And, this may be a lossy compression.
     
    root, Oct 19, 2003
    #13
  14. Peter

    Ian Guest

    As I have said elsewhere why not use Ip to serial boxes

    ClientPC->serial/IP--->IP
    network-->ip/serial->Modem->dialup->modem->server

    The ipnetwork must be in place as you say you want to do it over voip
    which is only a type of protocol not a type of network, if you could
    connect straight to the server without dialup you could connect the
    serial to IP box direct to the server. I have used these on security
    monitoring systems and they work fine.

    VOIP is the encapuslation of voice data into IP packets and depending
    on the codecs used the sampling rates are very low. what you are
    trying to do is pass serial data over IP, I believe Multitech do do
    some boxes that as well as giving a VOIP link will also carry fax and
    modem traffic but only at a slow speed. Serial to IP converters are
    the recognised way to do it in situations that need reliablity and
    security

    Ian



    Ian
     
    Ian, Oct 19, 2003
    #14
  15. Peter

    chris Guest


    Examples for me include, fax machines, visitors with laptops that need
    to dial home, security/alarm autodialers, etc.

    Cisco still does not handle fax or modem relay very well on their low
    end equipment. I've yet to find someone who got it working reliably
    on the ATA-186 for example. When we went Cisco VOIP, I found out
    Cisco was full of crap when they promised our setup would support
    analog modems. It handled faxes ok, but didn't get modem connections
    better than 14k until the recent IOS upgrades on our 3660. Now I can
    get V.90 connections connecting from a VG248 (48port FXS) through Call
    Manager to our 3660 gateway (out to pstn via T1).

    -Chris
     
    chris, Oct 19, 2003
    #15
  16. Cisco still does not handle fax or modem relay very well on their low
    My -186 works OK for sending faxes over Vonage. I get the impression
    that they've upgraded the software in recent months.
    I can believe that. The doc makes it clear that it recognizes faxes
    and treats them specially.
     
    John R. Levine, Oct 19, 2003
    #16
  17. Peter

    root Guest

    Is your FAX machine connected to the second RJ-11 port or the same port your
    phone is through a split line? I believe the 2nd RJ-11 port on an ATA-186
    does not support Voice CoDec and it uses a CCITT Group 4 (2nd) FAX CoDec to
    compress data from a FAX machine.

    What would you expect with a device that uses a CoDec for FAX that only runs
    @14.4Kbps?
    Sure. But, the doc did not specifically/clearly mention that it will connect
    @14.4Kbps which a standard FAX is using.
     
    root, Oct 20, 2003
    #17
  18. My -186 works OK for sending faxes over Vonage. I get the impression
    The phone port.
    That apparently depends on how the ATA is configured. Some VoIP
    providers will sell you voice on both ports. Also note that you can
    dial a #99 prefix to turn off fax recognition, which I find makes
    faxes work worse.
     
    John R. Levine, Oct 20, 2003
    #18
  19. Peter

    root Guest

    I believe the phone port is the one that does not use G.711 voice CoDec. Is
    there a way for you to check how much of a bandwitdh does the ATA-186 use
    when you are using the phone port and/or the voice port? I am using a
    lowe-end VoIPBlaster (VB) sold by Creative Labs and notice it only uses a
    total of about 4KBps (~32Kbps) for both up/down-streams.
    I wouldn't have known that since I don't use ATA-186 device. All my
    knowledge on this device is captured from posts in this NG as well as from
    reading its specs off the Cisco website.
     
    root, Oct 20, 2003
    #19
  20. Peter

    Miguel Cruz Guest

    My understanding is that the device doesn't have enough horsepower to do
    aggressive compression simultaneously on both ports. So one of them uses a
    less efficient (bandwidth-wise) codec. I am unfortunately away from any
    useful references so I can't provide more detail.

    miguel
     
    Miguel Cruz, Oct 20, 2003
    #20
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