A parameter is a named piece of data attached to a call that a Parameter condition can check against a filter operator. Some parameters arrive with the call automatically — basic call information or SIP header fields — while others are created mid-flow by an action that captures caller input or looks up external data. Together, these three parameter types are what let an IVR branch on more than just a caller's keypress.

---

Standard Parameter

Basic information about the call itself, available without any action needing to set it first.

Not every UC platform or carrier supplies every Standard Parameter on every call — DNIS in particular depends on whether the number dialed is passed through. When a Standard Parameter is not reliably present, a SIP Header parameter is often the more dependable alternative.

---

SIP Header

Fields read directly from the call's SIP header, useful when the information needed is not exposed as a Standard Parameter.

Only headers actually passed through by the carrier or UC platform are usable — confirm what is present in live traffic before building a condition around a specific header. A tool such as Wireshark, or a request to the carrier or UC platform for a sample trace, can confirm the exact header format in use.

---

Session Parameter

A value captured or set during the current call, available for the rest of that call's flow. Unlike Standard Parameters and SIP Headers, a Session Parameter does not exist until an action creates it.

The following actions write to a Session Parameter ID — see Actions for the full field reference on each:

Once set, a Session Parameter is available to any Parameter condition — or any later action that reads from a Session Parameter — for the remainder of that call.

---

Worked Example

A flow collects an account number from the caller and routes VIP accounts differently:

1. A Collect Digits action prompts for an account number and stores it under the Session Parameter ID AccountNumber
2. A Parameter condition is added below it, with Parameter Type set to Session Parameter, Session Parameter set to AccountNumber, Operator set to STARTS WITH, and Value set to 9
3. A Transfer to Skill sub-action is attached to that condition, targeting a VIP skill
4. If the condition is not met, the flow falls through to the next step — for example, a Transfer to Skill action targeting the standard support skill

This same pattern — an action that sets a parameter, followed by a condition that reads it back — applies whether the parameter came from caller input, a Data Dip lookup, or a SIP header supplied by the UC platform.