One transport.
Your choice of modem.

JSQ brings together commands and capabilities from JS8 and FSQ in one transport layer, independent of the modem carrying your signal.

JSQ transport
  • Chat & groups
  • Store-and-forward mail
  • Reliable files
  • Advertise & browse shared files
  • Relaying
  • Network discovery
File delivery
  • Retry missing blocks
  • Resume interrupted transfers
  • Verify complete files
Native ICS 213 forms

FSQ / FSQ Fast FM / HF

One audio tone at a time, with faster, wider profiles in FSQ Fast. Explore FSQ Fast

JG25 FM

A four-tone modem for fast data through an ordinary FM radio’s audio path. Explore JG25

AX.25 FM

AX1200 uses standard AX.25 packet framing for compatibility with existing packet-radio equipment and digipeaters. Explore AX1200

Illustrative waveforms.

The OpenJSQ application

A modern messenger
for amateur radio.

OpenJSQ brings familiar station and group conversations to your radio, with clear delivery status and radio details when you need them. Choose your conversation, write your message, and stay focused on the contact—not on memorizing commands.

Tour OpenJSQSee your first contact

Public release coming soon · Free to use · 64-bit Windows 10/11 · Public on-air specifications
Release status & what you need

The OpenJSQ Chats page, with callsign conversations at left and an FSQ exchange at right: incoming messages carrying signal, link quality and modem, and outgoing messages marked Sent.
Chats, part-way through an FSQ conversation. The traffic is an example exchange between test stations, not a record of on-air traffic. Open full-size screenshot
01 · Chats
TalkDirect, to a group, or to everyone on the channel. Use Live, or Verified for supported direct AX1200/JG25 chats when you want confirmation.
02 · Mail
Leave a letterYour station can hold mail until the recipient is heard, or hand it to a station that offers a mailbox for later delivery.
03 · Files
Send and share filesSend a file and re-send only the missing pieces if reception is imperfect, or let other stations browse a folder you choose to share.
04 · Relay
Reach furtherSend through a station that hears both of you. The original sender and final destination stay attached to the message.
05 · Network
See the pathsSee who your station hears and ask nearby stations who they hear, building a picture of possible radio paths.

Emergency communications · EMCOMM

Support for emergency communications.

When internet access is unavailable, OpenJSQ can help amateur-radio operators exchange updates, coordinate resources and share files over compatible radio links.

Coordinate your team with groups

Bring team updates, situation reports and resource requests into a shared group conversation. Operators join the group on compatible stations to follow the team’s traffic.

Station & group chat →

Leave an update for later

Hold mail until the recipient station returns, or hand it to a willing mailbox station. A team member can reconnect and catch up.

Store-and-forward mail →

Share the details intact

Send documents and files with missing-piece recovery and integrity verification. Advertise shared files so compatible stations can browse what they need.

Reliable files & sharing →

Find a path to coordinate

See which stations hear one another and consider supported relay options. Reception reports help operators identify possible paths for traffic.

Stations & relay paths →

Native ICS 213 formsCompose a structured general message in a fill-in sheet. Received forms open in the conversation or Inbox.Forms in the operator guide →

Read the status, not just the send action: transmission, mailbox custody and final delivery mean different things. Understand delivery status

Your station, connected

Connect to your radio.

Use an audio interface you already own, or connect an external packet TNC.

Through audio

  1. OpenJSQThe modem runs in the app
  2. Audio interfaceSignaLink · DigiRig · Radio USB audio
  3. Your radioAudio in and out · HF or FM

Key the transmitter with VOX or serial PTT, as your interface supports. Audio setup

Through a packet TNC

  1. OpenJSQSerial or network KISS connection
  2. External KISS TNCHardware TNC or software such as Dire Wolf
  3. Your FM radioAX.25 packet

Bluetooth serial TNCs use the serial route. BLE KISS requires a compatible device and build support. Packet setup

Compatibility depends on both stations. Use a compatible waveform and JSQ services supported by both peers. Legacy FSQ chat and commands do not provide JSQ verified delivery; standard AX.25 equipment also needs a JSQ-aware receiving application for JSQ services. Service support · Legacy FSQ · JSQ over AX.25

Who makes OpenJSQ

One amateur radio operator, and a public on-air record.

OpenJSQ is written by Jerome Goddard II, W4IJG. He designed the JSQ transport and the FSQ Fast and JG25-FM modems it carries, and publishes every on-air format here so any operator or developer can read, decode and implement it. Public specifications

AI-assisted development has played a substantial role in bringing OpenJSQ to life, guided by Jerome’s amateur-radio experience and vision for the project.

JSQ builds on the work of others: FSQ was designed by Murray Greenman, ZL1BPU, and Con Wassilieff, ZL2AFP, and JS8Call was created by Jordan Sherer, KN4CRD.

Get ready for OpenJSQ.

Free to use. Closed source. Every on-air code is published.

Release status & setup