$ python -m pynetdicom echoscu [options] addr port


The echoscu application implements a Service Class User (SCU) for the Verification service class. It establishes an association with a peer Application Entity (AE), sends a C-ECHO request and waits for a response. The application can be used to verify basic DICOM connectivity.

The source code for the application can be found here


The following example shows what happens when it is successfully run on an SCP at IP and listen port 11112 that supports the Verification service:

$ python -m pynetdicom echoscu 11112

When attempting to send a C-ECHO request to an SCP that doesn’t support the Verification service:

$ python -m pynetdicom echoscu 11112
E: No accepted presentation contexts

When the association request is rejected by the SCP (in this case because the called AE title wasn’t recognised):

$ python -m pynetdicom echoscu 11112
E: Association Rejected
E: Result: Rejected Permanent, Source: Service User
E: Reason: Called AE title not recognised

When attempting to associate with a non-DICOM peer:

$ python -m pynetdicom echoscu 11112
E: Association request failed: unable to connect to remote
E: TCP Initialisation Error: Connection refused

More information is available with the -d flag:

$ python -m pynetdicom echoscu 11112 -d
D: v0.7.0
I: Requesting Association
D: Request Parameters:
D: ======================= OUTGOING A-ASSOCIATE-RQ PDU ========================
D: ========================== END A-ASSOCIATE-AC PDU ==========================
I: Association Accepted
I: Sending Echo Request: MsgID 1
D: pydicom.read_dataset() TransferSyntax="Little Endian Implicit"
I: Received Echo Response (Status: Success)
I: Releasing Association



TCP/IP address or hostname of DICOM peer


TCP/IP port number of peer


General Options

-q    --quiet

quiet mode, prints no warnings or errors

-v    --verbose

verbose mode, prints processing details

-d    --debug

debug mode, prints debugging information

-ll   --log-level [l]evel (str)

One of ['critical', 'error', 'warning', 'info', 'debug'], prints logging messages with corresponding level or lower

Network Options

-aet  --calling-aet [a]etitle (str)

set the local AE title (default: ECHOSCU)

-aec  --called-aet [a]etitle (str)

set the called AE title for the peer AE (default: ANY-SCP)

-ta   --acse-timeout [s]econds (float)

timeout for ACSE messages (default: 30)

-td   --dimse-timeout [s]econds (float)

timeout for DIMSE messages (default: 30)

-tn   --network-timeout [s]econds (float)

timeout for the network (default: 30)

-pdu  --max-pdu [n]umber of bytes (int)

set maximum receive PDU bytes to n bytes (default: 16382)

Transfer Syntax Options

-xe   --request-little

request explicit VR little endian TS only

-xb   --request-big

request explicit VR big endian TS only

-xi   --request-implicit

request implicit VR little endian TS only

Miscellaneous Options

--repeat [n]umber (int)

repeat echo request n times


abort association instead of releasing it

DICOM Conformance

The echoscu application supports the Verification service as an SCU. The following SOP classes are supported:

Verification Service

SOP Classes


SOP Class


Verification SOP Class

Transfer Syntaxes


Transfer Syntax


Implicit VR Little Endian


Explicit VR Little Endian


Deflated Explicit VR Little Endian


Explicit VR Big Endian