That is not a complicated feature to implement, although is not part of what this version has been built up for.
Would it be enough to know the conference number your users can use or do you really really need them to be static?
Because for the first case an alternative solution to easily know from the UI what is the conference number that can be used for dial in (the moderator usually share this number using a different channel or the attendees use it when they can not join the voice bridge using the browser), if you are using short codes and you only want users to be able to use the voicebridge would be to override the default welcome message with a string that includes the %%CONFNUMBER%%
Something like this
[bigbluebutton token=”xxxxxxxxxxxx” welcome=”Welcome to the jungle
To join <b>%%CONFNAME%%</b> by phone, dial:
<b>%%DIALNUM%%</b>
Then enter <b>%%CONFNUM%%</b> as the conference pin number.”]
Again this workaround is, assuming the fixed number is not a hard requirement.
Now for adding the static conference number, the easiest way would be also to use a short code like this
[bigbluebutton token=”xxxxxxxxxxxx” welcome=”Welcome to the jungle
To join <b>%%CONFNAME%%</b> by phone, dial:
<b>%%DIALNUM%%</b>
Then enter <b>%%CONFNUM%%</b> as the conference pin number.” voicebridge=”74719″]
But you would need to edit the line 481 of your bigbluebutton-plugin.php file and replace this
$voicebridge = 0;
with this
$voicebridge = (isset($args[‘voicebridge’]))? html_entity_decode($args[‘voicebridge’]): 0;
That should do the trick. Just make sure to use one conference number per room.