vscode-tn3270

A native TN3270/TN3270E terminal emulator for Visual Studio Code. Connect to IBM z/OS, CICS, TSO, and ISPF directly from your editor.

Screenshots

Screenshots will be added once the Webview renderer is complete.

Features

• Native TN3270/TN3270E — Full protocol support with TLS 1.2/1.3
• Multiple concurrent sessions — Each session in its own VS Code tab
• Faithful 3270 emulation — Field attributes, extended colors, highlighting
• Multiple terminal models — IBM-3278-2 through IBM-3279-5-E (24×80 to 27×132)
• Theme integration — Adapts to VS Code light/dark/high-contrast themes
• Configurable keyboard — Standard 3270 key mappings via VS Code keybindings
• Session profiles — Workspace or user-scoped, with secure credential storage

Getting Started

1. Install the extension from the VS Code Marketplace
2. Open the Command Palette (Ctrl+Shift+P / Cmd+Shift+P)
3. Run TN3270: Manage Session Profiles to create a connection profile
4. Run TN3270: Open Session to connect

Requirements

• VS Code 1.85.0 or later
• Network access to a TN3270-compatible host (z/OS, Hercules, etc.)

Architecture

┌─────────────────────────────────────────────────┐
│  VS Code Webview (sandboxed iframe)             │
│  ┌───────────────────────────────────────────┐  │
│  │  Canvas/DOM Renderer  ←→  Keyboard Handler│  │
│  └──────────────────┬────────────────────────┘  │
│                     │ postMessage                │
├─────────────────────┼───────────────────────────┤
│  Extension Host     │ (Node.js)                 │
│  ┌──────────────────┴────────────────────────┐  │
│  │  Session Manager  ←→  3270 Datastream     │  │
│  │  TN3270E Negotiation  ←→  EBCDIC Codec   │  │
│  └──────────────────┬────────────────────────┘  │
│                     │ net.Socket / tls.TLSSocket │
├─────────────────────┼───────────────────────────┤
│  z/OS / Hercules    │                           │
│  TN3270 Host        ▼                           │
└─────────────────────────────────────────────────┘

Development

git clone https://github.com/billpereira/vscode-tn3270.git
cd vscode-tn3270
npm install
npm run compile
# Press F5 in VS Code to launch the Extension Development Host

License

MIT — see LICENSE

References

• zowe/tn3270-ng2 — Zowe TN3270 emulator
• mflorence99/tn3270 — TypeScript TN3270 library
• RFC 1576 — TN3270 Current Practices
• RFC 2355 — TN3270E