The C-ECHO procedures are initiated by the invoking DIMSE-service-user issuing a C-ECHO request primitive. On receipt of the C-ECHO request primitive the DIMSE-C protocol machine shall:

On receipt of a Message conveying a C-ECHO-RQ the DIMSE-C protocol machine shall issue a C-ECHO indication primitive to the performing DIMSE-service-user.

On receipt of a C-ECHO response primitive, issued by the performing DIMSE-service-user, the DIMSE-C protocol machine shall:

On receipt of a Message conveying a C-ECHO-RSP the DIMSE protocol machine shall issue a C-ECHO confirmation primitive to the invoking DIMSE-service-user, thus completing the C-ECHO procedure.