I know Odoo has several connectors that provide Asterisk integration. Is there any interest in integrating this with ERPNext?
A general idea would be creating a connection to Asterix with ERPNext.
Existing Customers: When existing customer calls, a popup with customers name appears. Option to take call, decline call or push back to call queue could appear. When call is taken, some other options could be displayed such as open the customer account details to log all information against the customers account relating to the call and another button offering to transfer the call in case another member of staff needs to deal with the customer.
Unknown Number: With this option, if a new telephone number calls an option to take call, decline call or push back to call queue could appear. When the call is answered, an option to create a new contact or lead can appear. Like with existing customers there should be an option to transfer the call at this point if the call needs to be transferred to a different department.
Both options could provide general information about the call that can be saved to a particular customer or lead such as the unique call log reference, caller ID, user that took the call, length of call, date and time time of call and even a recording of the call if enabled.
Another option that can be provided is click to call from the CRM in order to initiate the call directly from the ERP.
There are many other options that can come out of this including automated order or status checking if more extended development is done.