Dual-Port Serial I/O Module 621-9938 Honeywell SIOM

Product Overview

Honeywell 621-9938 is a dual-port Serial I/O Module (SIOM) designed for redundant serial I/O configurations. It controls the serial I/O card file and interfaces with the 621-9939 Serial Link Module, supporting 8/16/32-point arrangements.

Technical Specs

• Type: Serial I/O Module (SIOM) – dual port
• Ports: Dual communication ports for redundant links
• Point capacity: 8 / 16 / 32 configurable
• Interface: To 621-9939 SLM
• Termination: 200–300 Ω resistors required at link ends
• Addressing: DIP-switch selectable
• System: IPC / ISSC serial I/O racks

Key Features

• Dual-port design for high-availability serial networks
• Supports both redundant and non-redundant use
• Configurable I/O density and fault response
• Front status LEDs for diagnostics

FAQ

• Ports? Dual for redundant serial links.
• Point options? 8, 16 or 32.
• Pairs with? 621-9939 Serial Link Module.

Installation Guide

1. Install in slot N of the remote serial I/O card file.
2. Set DIP switches for address, point count and fault mode.
3. Connect dual serial cables and install terminating resistors.
4. Power up and verify communication with the SLM.
5. Confirm I/O mapping and status LEDs.

Selection Tips

• Required for redundant serial I/O card files.
• Use 621-9935 for non-redundant applications if dual ports are not needed.
• Critical spare for dual-redundant serial networks.