Re: ISDN phone lines

From: Richard H. (rh86_at_no.spam)
Date: 03/28/05 

Date: Mon, 28 Mar 2005 00:42:10 -0700

Nico Coesel wrote:
>>No. An ISDN line is not like a POTS line. It's a 2-wire always-on data
>>circuit. The endpoint maintains a full-time heartbeat with the telco
>>switch at the other end.
>
>
> Sorry, that's not true. Depending on the settings in the public
> network, an ISDN line is put in 'standby' and needs to be activated
> before use.

I presume you're referencing the "always on" point. No doubt ISDN can
be made to be a switched service; it seems to support a great many
variations. I understand it can also be made multi-drop with
addressable nodes (e.g., POS terminals).

However, in practice, I've never seen an installation implement other
than always-on. (IIRC, blowing the cobwebs out, this is the Q.921 link
signaling, which is typically kept alive regardless of upper-layer Q.931
sessions.)

In what scenario would it be beneficial to tear down the link layer?
IIRC, it takes several seconds to establish Q.921, so this wouldn't be
friendly to many voice applications.

Cheers,
Richard

Relevant Pages

  • Re: ISDN phone lines
    ... >>switch at the other end. ... No doubt ISDN can ... In what scenario would it be beneficial to tear down the link layer? ... IIRC, it takes several seconds to establish Q.921, so this wouldn't be ...
    (sci.electronics.design)
  • Re: External Modem Recomendation?
    ... >> than a clerk or manager at the telco?? ... contact our ISDN rep (with a large ... When major switch manufacturer's became aware of how that ... connection on a loop that just meets minimum standards. ...
    (comp.os.linux.misc)
  • Re: 2 Network Connections - How to Force Internet Explorer to use a Specific one
    ... switch using ethernet. ... The current connection to the Internet is 64k ISDN. ... The next step would be to add USB based wireless adapters to some ...
    (microsoft.public.windowsxp.general)
  • Re: Distribution Frage
    ... Bzgl. ISDN und Faxserver: so richtig toll und zuverlaessig (auch bei ... Der wesentlichste Unterschied ist der Support. ... IIRC gab es dazu auch einen Absatz in der FAQ: ...
    (de.comp.os.unix.linux.misc)
  • Re: The future of ISDN?
    ... I am a studio installer specializing in studios for Voice Over ... ISDN service installed is becoming more and more difficult. ... with the 'switch' playing traffic cop on the telco ...
    (comp.dcom.telecom.tech)
Quantcast