DECrepeater 90C Owners Manual

This owner's manual for the DECrepeater 90C provides comprehensive information on its installation, operation, and maintenance.

Key features and functionalities include:

1. Product Description: The DECrepeater 90C is a 7-port ThinWire Ethernet repeater designed for IEEE 802.3 CSMA/CD (10Base2) networks.
2. Operating Modes: It can function as a standalone, unmanaged unit with its own power supply, or as a managed repeater when installed in a Digital DEChub 90 Ethernet backplane alongside a DECbridge 90 work group bridge.
3. Installation:
   • Standalone: Simple setup involving connecting power and ThinWire Ethernet cables. Instructions for both table placement and wall mounting are provided.
   • Backplane: Detailed steps for installing the repeater into a DEChub 90 backplane, including "hot-swap" capability.
   • Connectivity: Emphasizes proper termination and grounding of ThinWire segments (50 ohms), noting internal termination for ports 1-6 and the need for external termination for Port 0.
4. Configuration & Operation: Describes configuration rules, port termination, and grounding. It also details "port partitioning," where a port is automatically disconnected due to faults (e.g., open/shorted cables) or can be manually partitioned via management. LED indicators provide crucial status feedback (power, network activity, port status).
5. Management (for DEChub configuration):
   • Managed remotely via the DECbridge 90's Maintenance Operations Protocol (MOP) using commands like DEFINE, LIST, SET, and SHOW.
   • Management functions include identifying repeaters, examining/controlling port status (enable/disable), resetting repeaters, and managing the work group address database.
   • Provides guidance on establishing MOP sessions from VMS and ULTRIX operating systems.
6. Troubleshooting: Dedicated sections with tables for diagnosing issues in both standalone and DEChub 90 configurations, often correlating problems with LED states and suggesting remedial actions.
7. Specifications: Appendices detail the DECrepeater 90C's physical dimensions, environmental requirements (operating and shipping), and electrical specifications (power supply).

The manual aims to guide users through setting up and maintaining their DECrepeater 90C efficiently, whether in a simple standalone setup or integrated into a more complex network hub environment.