[Home](./index.md) > [sip.js](./sip.js.md) > [NonInviteClientTransaction](./sip.js.noninviteclienttransaction.md) > [(constructor)](./sip.js.noninviteclienttransaction._constructor_.md) ## NonInviteClientTransaction.(constructor) Constructor Upon construction, the outgoing request's Via header is updated by calling `setViaHeader`. Then `toString` is called on the outgoing request and the message is sent via the transport. After construction the transaction will be in the "calling" state and the transaction id will equal the branch parameter set in the Via header of the outgoing request. https://tools.ietf.org/html/rfc3261\#section-17.1.2 Signature: ```typescript constructor(request: OutgoingRequestMessage, transport: Transport, user: ClientTransactionUser); ``` ## Parameters | Parameter | Type | Description | | --- | --- | --- | | request | OutgoingRequestMessage | The outgoing Non-INVITE request. | | transport | Transport | The transport. | | user | ClientTransactionUser | The transaction user. |