Introduction to Winlink Global Messaging System via Radio

By Maximo Barawid DU2UXH

From the Philippine Amateur Radio Association (PARA) website:



What is Winlink?

  • Worldwide system for sending/receiving e-mail via radio
  • Provides email from almost anywhere in the world.
  • Matured, well-tested and full feature system.
  • Adopted for contingency communication by many federal, state, and country government agencies (U.S.).
  • Used by by the National Guard (U.S.).
  • Used by infrastructure-critical NGOs such as International & American Red Cross, Southern Baptist Disaster Relief, AT&T Disaster Response & Recovery, FedEX, etc.


Primary Winlink Network

  • Amateur Radio – Over 10,000 amateur users are registered.
  • Winlink is used by most Off-Shore sailors. Operates within the international amateur radio frequency space.
  • Shares – Federal system providing HF radio contingency communication for federal agencies. SHARES operates on NTIS (National Technical Information Service), federal frequencies that are not part of the amateur radio frequency space.
  • MARS – Military Auxiliary Radio Service. Provides contigency communication for U.S. Military. Operates in NTIS MARS radio frequency space.


EMCOMM (Emergency Communications)

Reliability, Accuracy and Flexibility:

  • High reliability (99.99%) availability for 15 years)
  • 100% accurate message transmissions.
  • Radio connection bridge to internet e-mail.
  • Radio-only store and forward without internet.
  • Geographical dispersion and redundancy for reliability.
  • Peer-to-peer connections between radio end-users.
  • Various levels of security including message encryption interoperability: Connect different types of system


What Winlink Offers for EMCOMM

  • Bridge different radio capabilities (VHF/UHF/HF)
  • Bridge protocols: Pactore, Winmor, Ardop, VARA, Packet
  • Standard e-mail format with many features
  • Binary file attachments (picture, pdf, spreadsheets)
  • Encrypted attachments using the encryption program you choose. No need to convert to letter groups.
  • Time independence and frequency agility
  • Not limited by station-to-station propagation


Winlink Connection Modes.

  • Telnet – Non-radio connection through the internet.
  • VHF/UHF – FM Packet
  • HF WINMOR - “Poor man's Pactor”. Not as good as Pactor, but operates with an inexpensive sound card device like SignaLink USB, speeds between Pactor 2 and 3.
  • HF Pactor 4 – Fast and reliable but requires an expensive modem, $1500+
  • Peer to Peer – Can be used by all RF modes.


Definition of Terms:

  • Client system – Radio, computer with Winlink RMS Express software, TNC (or sound modem, sound card) and you, the end-user.
  • Radio Message Server (RMS) – Radio gateway between the client (end-user) and the Winlink system backbone.
  • Common Message Servers (CMS) – Winlink backbone.
  • Multiple CMS locations.
  • Redundant, fault-tolerant
  • Located on 3 continents.
  • One CMS is sufficient for normal system operation.

Winlink Architecture


Winlink RMS Express Interface:



Winlink RMS Express requirement:

  • Microsoft supported x86, 32 or 64 bit Windows OS (Windows 7 or Windows 2003 Server or later). Windows XP is not recommended due to MS ended it's support and for security reasons.
  • Computer with at least 700 MHz Pentium/Celeron class and at least 512MB of memory.
  • Microsoft .NET 3.5 framework.
  • Packet TNC (Kantronics, TNC-X, MFJ, etc), or SignaLink USB or similar soundcard. Might require USB to Serial converter.
  • Note: Some newer radios have built-in sound cards/TNC.
  • RMS Express can be downloaded;
  • All software is free, donation is suggested.
  • Software modems are also available.
  • Packet:
  • VARA: (payware for full version)
  • ARDOP: Amateur Radio Digital Open Protocol is integrated with RMS Trimode

For more information about Winlink RMS Express, go to:



There are tons of howto videos in the internet about RMS Express and NBEMS (Narrow Band Emergency Messaging Software). The best videos about Winlink RMS Express is by Rick Frost, K4REF. He has a series of videos about this program and how to use it. You can start with this;

What is Winlink:

Tutorials on PDF: