Minimal Lower Layer Protocol (MLLP)

Minimal Lower Layer Protocol (MLLP) is a minimalistic transport protocol for HL7 v2 messaging.

MLLP Transport Specification

Message Format

<START_BLOCK><DATA><END_BLOCK><CR>

where:

<START_BLOCK> is 0x0b
<DATA> is an HL7 message where segments are separated by <CR>
<END_BLOCK> is 0x1c
<CR> is 0x0d

Minimal MLLP Bash Sender

${1} is the host
${2} is the port
${3} is the name of HL7 message file (see <DATA> above)

#!/bin/bash
set -o errexit
exec 3<>/dev/tcp/${1}/${2}
echo -n -e "\x0b$(cat ${3})\x1c\x0d" >&3
cat | tr '\r' '\n' <&3
echo

Minimal MLLP Bash Receiver

nc -l -k -p PORT | tr '\r' '\n'

Editing HL7 Files

HL7 message files can be edited with any text editor as long as the editor doesn't apply any line end conversions. E.g. with vim use -b (binary mode).

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Source: mllp.md Created: 2024-01-09T08:54:42+02:00 Changed: 2025-02-13T15:46:03+02:00