Protocol Glossary

Hotline Protocol

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Core Documentation

• Documentation Home
• Glossary / Terms
• Protocol History

Technical Specifications

• Transaction IDs
• Field Definitions
• Access Bits
• Error Codes

Binary & Data

• FILP/RFLT Specs
• News Headers
• Logic Sequences

External Networking

• Tracker (HTRK)
• HTTP Tunneling
• Global Server

Assets

• Icon Gallery

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Glossary of Terms

Architecture & Networking

• Big-Endian (Network Byte Order): The byte-ordering used by the Hotline protocol where the most significant byte is stored at the smallest memory address.
• Base Port: The primary TCP port configured for a server (default is often 5500). All other service ports (+1, +2, +3) are derived from this number.
• Handshake (TRTP): The initial "Hotline Connection" packet (54 52 54 50) required to establish a session before any transactions can occur.
• Transaction: The fundamental unit of communication in Hotline, consisting of a 20-byte header and a list of sub-parameters.

Data Structures

• Forks (Data vs. Info): A concept inherited from the classic Mac OS File System.
  • Data Fork: Contains the actual bytes of a file.
  • Info Fork: Contains metadata like the File Type, Creator code, and original timestamps.
• Magic Number: A unique 4-byte string (e.g., FILP, HTRK) used to identify the format of a binary data block.
• NEG (Negated Login): A basic obfuscation used in User Management (Trans 352) where every character in a login string is bitwise negated (~char).

Components

• Tracker: A central registry server that maintains a list of active Hotline servers and their current user counts.
• Tunneling: The process of wrapping Hotline transactions inside standard HTTP GET/POST requests to bypass restrictive firewalls.