OnSIP can be integrated with the Odoo CRM application by using the following documentation:

https://www.odoo.com/documentation/user/11.0//crm/optimize/onsip.html

In short, add OnSIP as a module and then add your OnSIP username, authorized username, and password in the settings.  

Once OnSIP is configured, clicking on a number will launch the phone application within Odoo and the call will be placed out the OnSIP service. 

Please note, that you must be an OnSIP subscriber with at least a pre-paid PSTN balance in order to make calls via this method.

Check out our Blog about Odoo Integration.

Notes:

• When placing calls, confirm that the Odoo interface is sending a "1" plus area code plus number, e.g. 12125551234. 
  
  
• If you are an existing Odoo customer, you need to upgrade to version 11.  If you are a new customer, you will start on version 11.