echoscu(1)

📦
version 3.7.1 · 10 versions
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💖 echoscu(1) — OFFIS DCMTK 💖

okay bestie, sit down, hydrate, because we're about to talk about echoscu from the OFFIS DCMTK manual set, and honestly? she's iconic. she's the "hey are you there??" of the DICOM world. let's go 🦋

✨ NAME ✨

echoscu — DICOM verification (C-ECHO) SCU, aka the friend that texts "u up?" to your PACS 🫶

🌸 SYNOPSIS 🌸

echoscu [options] peer port

💅 DESCRIPTION 💅

so the echoscu application is a Service Class User (SCU) for the Verification SOP Class — like, the whole job is verification, that's her lane, she stays in it 👑

basically she sends a DICOM C-ECHO message to a Service Class Provider (SCP) and then waits for a response. patient queen energy, she will wait. and the app can be used to verify basic DICOM connectivity — which is literally the "can we even talk to each other" vibe check of the whole network 🔥

🎀 PARAMETERS 🎀

  • peer — hostname of DICOM peer 💫
  • port — tcp/ip port number of peer 💫

✨ OPTIONS ✨

🌈 general options

  • -h, --help — print this help text and exit. classic. we love a quick out ✨
  • --version — print version information and exit. who are you, where did you come from 👀
  • --arguments — print expanded command line arguments. for the nosy ones (me, I'm nosy) 🙈
  • -q, --quiet — quiet mode, print no warnings and errors. she's giving stealth mode 💀
  • -v, --verbose — verbose mode, print processing details. now she's yapping (affectionate) 💬
  • -d, --debug — debug mode, print debug information. full brain dump, no filter 🧠
  • -ll, --log-level [l]evel: string constant — use level l for the logger. the valid levels are fatal, error, warn, info, debug, trace 📋
  • -lc, --log-config [f]ilename: string — use config file f for the logger 📁

🌈 network options

IP protocol version:

  • -i4, --ipv4 — use IPv4 only (default) 💜
  • -i6, --ipv6 — use IPv6 only 💜
  • -i0, --ip-auto — use DNS lookup to determine IP protocol. let the DNS girlies decide 💜

application entity titles:

  • -aet, --aetitle [a]etitle: string — set my calling AE title (default: ECHOSCU) 💖
  • -aec, --call [a]etitle: string — set called AE title of peer (default: ANY-SCP) 💖

association negotiation debugging:

  • -pts, --propose-ts [n]umber: integer (1..53) — propose n transfer syntaxes 🎀
  • -ppc, --propose-pc [n]umber: integer (1..128) — propose n presentation contexts 🎀
lowkey note: those ranges are 1..53 and 1..128, don't get creative with them bestie 🙅

other network options:

  • -to, --timeout [s]econds: integer (default: unlimited) — timeout for connection requests ⏳
  • -ts, --socket-timeout [s]econds: integer (default: 60) — timeout for network socket (0 for none) 🧦
  • -ta, --acse-timeout [s]econds: integer (default: 30) — timeout for ACSE messages ⏱️
  • -td, --dimse-timeout [s]econds: integer (default: unlimited) — timeout for DIMSE messages ⏱️
  • -pdu, --max-pdu [n]umber of bytes: integer (4096..131072) — set max receive pdu to n bytes (default: 16384) 📦
  • --repeat [n]umber: integer — repeat n times. again! again! 🔁
  • --abort — abort association instead of releasing it. dramatic exit, no closure, we love it 💀

🔐 transport layer security (TLS) options

transport protocol stack:

  • -tls, --disable-tls — use normal TCP/IP connection (default) 🐢
  • +tls, --enable-tls [p]rivate key file, [c]ertificate file: string — use authenticated secure TLS connection 🔒
  • +tla, --anonymous-tls — use secure TLS connection without certificate. mysterious. no ID, still encrypted 🕶️

private key password (only with --enable-tls):

  • +ps, --std-passwd — prompt user to type password on stdin (default) ⌨️
  • +pw, --use-passwd [p]assword: string — use specified password 🙊
  • -pw, --null-passwd — use empty string as password 🫥

key and certificate file format:

  • -pem, --pem-keys — read keys and certificates as PEM file (default) 📜
  • -der, --der-keys — read keys and certificates as DER file 📜

certification authority:

  • +cf, --add-cert-file [f]ilename: string — add certificate file to list of certificates ➕
  • +cd, --add-cert-dir [d]irectory: string — add certificates in d to list of certificates ➕
  • +crl, --add-crl-file [f]ilename: string — add certificate revocation list file (implies --enable-crl-vfy) 🚫
  • +crv, --enable-crl-vfy — enable leaf CRL verification 🍃
  • +cra, --enable-crl-all — enable full chain CRL verification ⛓️

security profile:

  • +ph, --list-profiles — list supported TLS profiles and exit 📋
  • +pg, --profile-8996 — BCP 195 RFC 8996 TLS Profile (default) 🌟
  • +pm, --profile-8996-mod — Modified BCP 195 RFC 8996 TLS Profile 🌟
# only available if underlying TLS library supports # all TLS features required for this profile — so it might just not be a thing on your box, don't @ me 🥲
  • +py, --profile-bcp195-nd — Non-downgrading BCP 195 TLS Profile (retired) 👵
  • +px, --profile-bcp195 — BCP 195 TLS Profile (retired) 👵
  • +pz, --profile-bcp195-ex — Extended BCP 195 TLS Profile (retired) 👵
  • +pb, --profile-basic — Basic TLS Secure Transport Connection Profile (retired) 👵
# only available if underlying TLS library supports 3DES — yes, 3DES, yes it's giving 2011, that's why it says retired 🫠
  • +pa, --profile-aes — AES TLS Secure Transport Connection Profile (retired) 👵
  • +pn, --profile-null — Authenticated unencrypted communication (retired, was used in IHE ATNA) 👵
ok bestie, clock the tea: a whole bunch of these profiles are literally marked retired. they're still documented, but do not come for me if you pick one and it's giving museum exhibit 🏛️

ciphersuite:

  • +cc, --list-ciphers — list supported TLS ciphersuites and exit 📋
  • +cs, --cipher [c]iphersuite name: string — add ciphersuite to list of negotiated suites 🔐

server name indication:

  • --no-sni — do not use SNI (default) 🙈
  • --request-sni [s]erver name: string — request server name s 📛

pseudo random generator:

  • +rs, --seed [f]ilename: string — seed random generator with contents of f 🌱
  • +ws, --write-seed — write back modified seed (only with --seed) ✍️
  • +wf, --write-seed-file [f]ilename: string (only with --seed) — write modified seed to file f ✍️

peer authentication:

  • -rc, --require-peer-cert — verify peer certificate, fail if absent (default) 🪪
  • -ic, --ignore-peer-cert — don't verify peer certificate. trust falls, but make it network security 🙃

offline certificate verification:

  • +vc, --verify-cert [f]ilename: string — verify certificate against CA settings 🔍
# Load a client certificate and check whether it would be accepted # when received during a TLS handshake. Print result and exit.
  • +rc, --is-root-cert [f]ilename: string — check if certificate is self-signed root CA 🔍
# Load a client certificate and check whether it is a valid, # self-signed root CA certificate. Print result and exit.

🌟 NOTES 🌟

💖 DICOM Conformance 💖

so the echoscu application supports the following SOP Classes as an SCU — just the one, she's focused:

VerificationSOPClass                                1.2.840.10008.1.1

and by default? the echoscu application will only propose this transfer syntax:

LittleEndianImplicitTransferSyntax                  1.2.840.10008.1.2

BUT. and this is the fun part. if the --propose-ts option is used, the following transfer syntaxes will also be proposed, depending on the numeric value n that is passed to this option. get comfy, this list is long and lowkey the main character of this section 👑

LittleEndianExplicitTransferSyntax                  1.2.840.10008.1.2.1
BigEndianExplicitTransferSyntax                     1.2.840.10008.1.2.2
JPEGProcess1TransferSyntax                          1.2.840.10008.1.2.4.50
JPEGProcess2_4TransferSyntax                        1.2.840.10008.1.2.4.51
JPEGProcess3_5TransferSyntax                        1.2.840.10008.1.2.4.52
JPEGProcess6_8TransferSyntax                        1.2.840.10008.1.2.4.53
JPEGProcess7_9TransferSyntax                        1.2.840.10008.1.2.4.54
JPEGProcess10_12TransferSyntax                      1.2.840.10008.1.2.4.55
JPEGProcess11_13TransferSyntax                      1.2.840.10008.1.2.4.56
JPEGProcess14TransferSyntax                         1.2.840.10008.1.2.4.57
JPEGProcess15TransferSyntax                         1.2.840.10008.1.2.4.58
JPEGProcess16_18TransferSyntax                      1.2.840.10008.1.2.4.59
JPEGProcess17_19TransferSyntax                      1.2.840.10008.1.2.4.60
JPEGProcess20_22TransferSyntax                      1.2.840.10008.1.2.4.61
JPEGProcess21_23TransferSyntax                      1.2.840.10008.1.2.4.62
JPEGProcess24_26TransferSyntax                      1.2.840.10008.1.2.4.63
JPEGProcess25_27TransferSyntax                      1.2.840.10008.1.2.4.64
JPEGProcess28TransferSyntax                         1.2.840.10008.1.2.4.65
JPEGProcess29TransferSyntax                         1.2.840.10008.1.2.4.66
JPEGProcess14SV1TransferSyntax                      1.2.840.10008.1.2.4.70
RLELosslessTransferSyntax                           1.2.840.10008.1.2.5
DeflatedExplicitVRLittleEndianTransferSyntax        1.2.840.10008.1.2.1.99
JPEGLSLosslessTransferSyntax                        1.2.840.10008.1.2.4.80
JPEGLSLossyTransferSyntax                           1.2.840.10008.1.2.4.81
JPEG2000LosslessOnlyTransferSyntax                  1.2.840.10008.1.2.4.90
JPEG2000TransferSyntax                              1.2.840.10008.1.2.4.91
JPEG2000Part2MulticomponentImageComp.LosslessOnlyT. 1.2.840.10008.1.2.4.92
JPEG2000Part2MulticomponentImageComp.TransferSyntax 1.2.804.10008.1.2.4.93
MPEG2MainProfileAtMainLevelTransferSyntax           1.2.840.10008.1.2.4.100
MPEG2MainProfileAtHighLevelTransferSyntax           1.2.840.10008.1.2.4.101
MPEG4HighProfileLevel4_1TransferSyntax              1.2.840.10008.1.2.4.102
MPEG4BDcompatibleHighProfileLevel4_1TransferSyntax  1.2.840.10008.1.2.4.103
MPEG4HighProfileLevel4_2_For2DVideoTransferSyntax   1.2.840.10008.1.2.4.104
MPEG4HighProfileLevel4_2_For3DVideoTransferSyntax   1.2.840.10008.1.2.4.105
MPEG4StereoHighProfileLevel4_2TransferSyntax        1.2.840.10008.1.2.4.106
HEVCMainProfileLevel5_1TransferSyntax               1.2.840.10008.1.2.4.107
HEVCMain10ProfileLevel5_1TransferSyntax             1.2.840.10008.1.2.4.108
FragmentableMPEG2MainProfileMainLevelTransferSyntax 1.2.840.10008.1.2.4.100.1
FragmentableMPEG2MainProfileHighLevelTransferSyntax 1.2.840.10008.1.2.4.101.1
FragmentableMPEG4HighProfileLevel4_1TransferSyntax  1.2.840.10008.1.2.4.102.1
FragmentableMPEG4BDcompatibleHighProfileLevel4_1Tr. 1.2.840.10008.1.2.4.103.1
FragmentableMPEG4HighProfileLevel4_2_For2DVideoTr.S 1.2.840.10008.1.2.4.104.1
FragmentableMPEG4HighProfileLevel4_2_For3DVideoTr.S 1.2.840.10008.1.2.4.105.1
FragmentableMPEG4StereoHighProfileLevel4_2TransferS 1.2.840.10008.1.2.4.106.1
HighThroughputJPEG2000ImageCompressionLossless.Tr.S 1.2.840.10008.1.2.4.201
HighThroughputJPEG2000RPCLImageCompressionLoss.Tr.S 1.2.840.10008.1.2.4.202
HighThroughputJPEG2000ImageCompressionTransferSynt. 1.2.840.10008.1.2.4.203
🫶 tiny heads-up because I love you: those names are copied exactly as they appear, truncations and all — JPEG2000Part2MulticomponentImageComp.LosslessOnlyT. really does end in a dot, and yes, 1.2.804.10008.1.2.4.93 really is written like that. do not "fix" them, they're not typos on my end, they're just how the manual prints them. iykyk 💅

✨ LOGGING ✨

Okay bestie, so the level of logging output from the various command line tools and underlying libraries can be set by you. By default, only errors and warnings are written to the standard error stream. Using option --verbose also reports informational messages like processing details. Option --debug can be used to get more details on the internal activity, e.g. for debugging purposes. Other logging levels can be selected using option --log-level. In --quiet mode only fatal errors are reported. In such very severe error events, the application will usually terminate. For more details on the different logging levels, see documentation of module "oflog".

If the logging output should be written to file (optionally with logfile rotation), to syslog (Unix) or the event log (Windows), option --log-config can be used. This configuration file also allows for directing only certain messages to a particular output stream and for filtering certain messages based on the module or application where they are generated. An example configuration file is provided in <etcdir>/logger.cfg.

🛠️ COMMAND LINE 🛠️

All command line tools use the following notation for parameters: square brackets enclose optional values (0-1), three trailing dots indicate that multiple values are allowed (1-n), and a combination of both means 0 to n values.

Command line options are distinguished from parameters by a leading + or - sign, respectively. Usually, order and position of command line options are arbitrary (i.e. they can appear anywhere). However, if options are mutually exclusive, the rightmost appearance is used. This behavior conforms to the standard evaluation rules of common Unix shells.

In addition, one or more command files can be specified using an @ sign as a prefix to the filename (e.g. @command.txt). Such a command argument is replaced by the content of the corresponding text file (multiple whitespaces are treated as a single separator unless they appear between two quotation marks) prior to any further evaluation. Please note that a command file cannot contain another command file. This simple but effective approach allows one to summarize common combinations of options/parameters and avoids longish and confusing command lines (an example is provided in file <datadir>/dumppat.txt).

💅 EXIT CODES 💅

The echoscu utility uses the following exit codes when terminating. This enables the user to check for the reason why the application terminated.

🌈 general 🌈

  • EXITCODE_NO_ERROR — 0
  • EXITCODE_COMMANDLINE_SYNTAX_ERROR — 1

🍓 input file errors 🍓

  • EXITCODE_CANNOT_READ_INPUT_FILE — 20 (*)
  • EXITCODE_INVALID_INPUT_FILE — 22

🎀 output file errors 🎀

  • EXITCODE_CANNOT_WRITE_OUTPUT_FILE — 40 (*)

🦋 network errors 🦋

  • EXITCODE_CANNOT_INITIALIZE_NETWORK — 60 (*)
  • EXITCODE_ASSOCIATION_ABORTED — 70
(*) Actually, these codes are currently not used by echoscu but serve as a placeholder for the corresponding group of exit codes.

🌱 ENVIRONMENT 🌱

The echoscu utility will attempt to load DICOM data dictionaries specified in the DCMDICTPATH environment variable. By default, i.e. if the DCMDICTPATH environment variable is not set, the file <datadir>/dicom.dic will be loaded unless the dictionary is built into the application (default for Windows).

The default behavior should be preferred and the DCMDICTPATH environment variable only used when alternative data dictionaries are required. The DCMDICTPATH environment variable has the same format as the Unix shell PATH variable in that a colon (:) separates entries. On Windows systems, a semicolon (;) is used as a separator. The data dictionary code will attempt to load each file specified in the DCMDICTPATH environment variable. It is an error if no data dictionary can be loaded.

Copyright (C) 1994-2026 by OFFIS e.V., Escherweg 2, 26121 Oldenburg, Germany.

That’s the whole page, bestie! This echoscu(1) manual is Version 3.7.1, dated Sat Oct 17 2026 09:34:01 — footer tea, served fresh 💅✨

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