[Asterisk-Users] No dialtone in a E1

[Peter Svensson]

On Fri, 11 Feb 2005, Marco Castillo wrote:

> Thank you Peter, how can I add the options to Dial to generate ringback???
> do you have an example???

run "show application dial" in the cli. It should explain the options, 
including the "r" option.

> By the way, it is a PRI E1, with 30 bchannels and 1 dchannel. For a little
> background, I'm intending to replace my actual PBX with Asterisk, and
> everything is just working fine, until yesterday when I realized that when a
> call was made from some external lines, this lines didn't receive a
> dialtone. For this reason, I began to make some exhaustive test cases, and
> began to make calls from distinct providers to my E1. In all this testing I
> received a dialtone, except for a GSM cellular phone from a specific Telco.
> I tested some others GSM cellulars from the same Telco, and got always the
> same functionality, they didn't receive a dialtone. I think that if Asterisk
> can generate a ringback, this is going to solve all my problems with this
> little issue.

The pstn has the option of either generating progress tones locally or 
allowing the remote end to send them. Since asterisk always claims "In 
band progress tines available", it has to generate them if the destination 
does not. If the destination is a pbx it will usually fill the back 
channel with progress tones (i.e. ringback) which will pass streight 
through asterisk. For destinations that does not (such as most voip 
phones) asterisk has to fill in the back channel with progress tones. 

Using or not using the audio in this reverse channel is up to the 
originating telco.

Peter