Codec G722 HD Audio

G.722 HD Audio. What’s the big deal?

G.722, HD Voice and HD Audio have become the latest buzzwords in the VoIP (Voice Over Internet Protocol) market in the last year. They are all words to describe the same thing - wideband audio that delivers voice calls using VoIP with audio quality that is greatly superior that of a regular landline or mobile phone call.  

Asterisk TLS Realizando llamadas seguras.

 

 Overview

So you'd like to make some secure calls.
Here's how to do it, using Blink, a SIP soft client for Mac OS X, Windows, and Linux.
These instructions assume that you're running as the root user (sudo su -).

Part 1 (TLS)

Transport Layer Security (TLS) provides encryption for call signaling. It's a practical way to prevent people who aren't Asterisk from knowing who you're calling. Setting up TLS between Asterisk and a SIP client involves creating key files, modifying Asterisk's SIP configuration to enable TLS, creating a SIP peer that's capable of TLS, and modifying the SIP client to connect to Asterisk over TLS.  

Como cambiar el modo de una tarjeta digital de T1 o E1 sin move el jumper de configuracion.

The recommended way to set line mode on your Digium 1-, 2-, and 4-port (span) digital telephony cards is to set the jumper(s) on the card for either T1 or E1 mode for each span on the card. With the jumper off, the span is ready for T1 mode; with the jumper on, the span is ready for E1 mode. For more details about the jumpers, see the user manual for the single, dual, or quad span digital cards.

However, sometimes a card will have been installed in a server without first setting the jumper(s) correctly, and it may be inconvenient to remove the card from the server to access its jumper(s).  In this case, the "default_linemode" option can be passed when the card's device driver is loaded.  For single-span cards, the device driver is wcte12xp; for dual-, quad-, and 8-span cards, the device driver is wct4xxp.

Note: The eight-span card (TE820) does not have jumpers. The "default_linemode" module parameter, for the wct4xxp device driver, is the only method to set the TE820 line mode.

Depending on how your Asterisk server loads the DAHDI device drivers, the "default_linemode" option must be set/passed in one of two places:

• If your Asterisk server uses the DAHDI init script to load the DAHDI device drivers on boot (or if you execute the "service dahdi start" command, which runs the init script), you must set the "default_linemode" option in the /etc/modprobe.d/dahdi.conf file.

    /etc/modprobe.d/dahdi.conf : 

DAHDI

Short for "Digium Asterisk Hardware Device Interface"

The Change

DAHDI is the new name for 'Zaptel' as of May 19th 2008.
The post at http://blogs.digium.com/2008/05/19/zaptel-project-being-renamed-to-dahdi/ details the reason for the change. Asterisk 1.4 releases later than 1.4.21, and all releases of Asterisk 1.6, will automatically use DAHDI in preference to Zaptel, even if Zaptel is still installed on the system.

Details should be available at http://www.asterisk.org/zaptel-to-dahdi  

Asterisk Dialplan Injection.

Hace una semana Olle Johansson anunció un fallo de seguridad bastante interesante, pero no me atreví a escribir sobre él hasta que no lo hubiésemos probado y al fín lo hicimos, y los resultados son escalofriantes:
Imaginemos que utilizamos un terminal IP (o softphone) con una cuenta limitada a extensiones SIP, en principio sólo podríamos llamar a extensiones SIP, pero el bug explica cómo aprovechar una mala programacion del dialplan y poder llamar a donde queramos:
El fallo de seguridad ocurre principalmente si tenemos una línea como esta:

Use asterisk to dial outbound number with extension

Sometimes, you want to reach an outbound number and when it answers, press some digits to naviguate through IVR.
The most common case where this can happens is when you want the callers from your PBX to reach a number and go direclty to a given extension. This prevents the caller to enters himself the extension number of the foreign side.
To make it done, you can use asterisk Dial option D.