[asterisk-users] loop-start and ground-start

[Russ Meyerriecks]

> First of all could you please explain loop-start and ground-start for me?
> What are they used for?
>
Loop start is the simplest type of analog phone signalling. It's used to
connect an FXS (like a central office) with a very simple FXO device (like
a handset). In this signalling mode, the FXS device basically sends a DC
current down the line to the FXO. When the FXO device (handset) goes
offhook, it shorts both wires (tip and ring). The FXS device will then
detect this "offhook" state from the DC current that returns on "the loop".

Kewl start is Asterisk's name for Loop Start with the "disconnect
supervision" feature. This is most likely what you want to select over
regular loop start. http://en.wikipedia.org/wiki/Disconnect_supervision

Ground start is typically used to connect an FXS (like a central office) to
something more complicated like a PBX. In this signalling mode, both
devices are able to provide a DC current on the line. This affords some
extra line supervision options that are handy to have with a PBX. From what
I understand, this is a pretty rare mode these days ...


> Next, I have the following configurations:
>
>
>
> dahdi-channels.conf :
>
> context=pstn-channels
> signalling=fxs_ks
> channel=>130
> context=phone-channels
> signalling=fxo_ks
> channel=>127
>
> chan_dahdi.conf :
>
> [channels]
> cidsignalling=dtmf
> cidstart=dtmf
>
> signalling=fxo_ls
> pulsedial=no
> usecallerid=yes
> context=pstn-channels
> channel=>130
>
Signalling is determined by the device you want to signal TO. So if channel
130 is connected to the pstn, you likely want fxs signalling. This would
mesh with how you have dahdi-channels.conf and /etc/dahdi/system.conf.


> signalling=fxs_ls
> context=phone-channels
> channel=>127
>
Same here as above. If channel 127 is connected to phones (fxo) you
probably want fxo signalling here.
Also, dahdi-channels.conf is generated by dahdi's best guess and is
typically intended to be #included at the bottom of chan_dahdi.conf. Not
sure if you left that out on purpose.


>
> extensions.conf :
>
> [pstn-channels]
> exten=>_.,1,Dial(DAHDI/127/${EXTEN})
>
> [phone-channels]
> exten=>_.,1,Dial(DAHDI/130/${EXTEN})
>
> /dahdi/system.conf
> fxoks=125-128
> fxsks=129-132
>
> I can hear the dial tone from the phone with these configurations. As soon
> as I comment "signalling" type in chan_dahdi.conf, dial tone comes up.
> What's the problem with these configurations?
>
>
> --
> _____________________________________________________________________
> -- Bandwidth and Colocation Provided by http://www.api-digital.com --
> New to Asterisk? Join us for a live introductory webinar every Thurs:
>                http://www.asterisk.org/hello
>
> asterisk-users mailing list
> To UNSUBSCRIBE or update options visit:
>    http://lists.digium.com/mailman/listinfo/asterisk-users
>



-- 
Russ Meyerriecks
Digium, Inc. | Linux Kernel Developer
445 Jan Davis Drive NW - Huntsville, AL 35806 - USA
direct: +1 256-428-6025
Check us out at: www.digium.com & www.asterisk.org
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.digium.com/pipermail/asterisk-users/attachments/20131005/bdeac4b9/attachment.html>