IMPAX port numbers

A port number identifies a specific process to which a network message is forwarded. For example, IMPAX listens for DICOM on port 104. TCP/IP processes like telnet, ftp, and rlogin all have specific port assignments that identify where the process lives and how messages can be passed between the computer's appropriate client and server transport layers.

When a modality sends a study to the Network Gateway, it sends it to port 104. On the Network Gateway, port 104 is assigned to the SCP, which performs HIS verification and routing. The modality must be configured to send DICOM to port 104 on the Network Gateway. You cannot bypass the Network Gateway to transmit directly from the modality to one or more Clients.

The imaging modality can listen for DICOM on a port other than 104. This becomes significant only if you try to query, transmit, and retrieve from IMPAX to the modality. If you perform a DICOM ping of the modality and get the response "Could not connect to port 104 on hostxxxx", then the modality is listening for DICOM on a port other than 104.