According to the description of your setup, your client and your server are assigned the same AET ("PETPACSLT"). This is not a good practice, as the AET is expected to be unique across your Intranet.
Client AE-TItle: PETPACSLT
Client IP Address: 127.0.0.1
Client DICOM port: 2000 (to Retrieve images from Orthanc with the Query/Retrieve)
And that you want to assign the following configuration to the Orthanc server:
Orthanc AET : ORTHANC
Orthanc IP Adress: 127.0.0.1
Orthanc DICOM Port: 2001 (to receive Queries from your client for the Query/Retrieve)
In such a case, you would use the following configuration for Orthanc:
"DicomAet" : "ORTHANC",
"DicomCheckCalledAet" : false,
"DicomPort" : 2001,
"DicomModalities" : {
"Client1" : [ "PETPACSLT", "127.0.0.1", 2000 ]
}
The "Client1" can be an arbitrary string.
By default or if "DicomCheckCalledAet" is set to "false", then any modality can send DICOM images to Orthanc. So, your future radiography device will work out-of-the-box without changing the configuration.
HTH,
Sébastien-