Node parameters in general can accept literal values (for example, 12345) or variable values (for example, CalledNumber).
The following symbol denotes a literal value:
The following symbol denotes a variable value:
Clicking on the L or V symbol next to the parameter allows you to choose between providing a literal or a variable value.
When set to literal, you can simply type in the value that you want the parameter to take.
When set to variable, you can select a value from all call flow variables of the appropriate type (or choose to add a new call flow variable).
For some parameters, the node type writes information into the provided variable so it is available for use elsewhere in your call flow (for example, the Input String parameter of the the DTMF String node type). Such parameters may not be configured to accept a literal value. Additionally, some parameter value types such as Call have no literal representation, so parameters of those types only accept variable values.
Some literal parameters (of types AudioFile, Boolean, Integer or String) can be configured to accept user-configurable values. This means that even though you, the call-flow creator, define the default values for these parameters, they can be overridden by a company administrator with the Service Numbers:Modify privilege to suit their own requirements. (The parameters are tied to the service numbers associated with them rather than the call flow.)
The following symbol denotes a user-configurable value:
One parameter type (Queue) can only accept a user-configurable value (is only configurable at the company level). This is because you (the platform owner/administrator) cannot possibly know the specific queues that are used by an individual company. It is therefore the responsibility of the company administrator to define these queues.