Honeywell 621-9938 Serial I/O Module — industrial automation module front view

Honeywell 621-9938 — front panel with LED indicators

Honeywell 621-9938 — backplane connector side

Honeywell 621-9938 — PCB board detail

Honeywell

Honeywell 621-9938 Serial I/O Module

SKU: 621-9938 In Stock

Honeywell

Genuine Honeywell 621-9938. Serial I/O Module. Factory-tested, 48h burn-in. 12-month warranty. Ships within 24h.

Technical Specifications

621-9938	Serial I/O Module (SIOM) is a dual-port communication card used in Honeywell TDC 3000 and IPC 620/621 systems. It manages the serial I/O card file and interfaces with the 621-9939 Serial Link Module (SLM), ensuring reliable communication between controllers and serial-based field devices.
Model	621-9938
Type	Serial I/O Module (SIOM)
Ports	Dual communication ports for redundant serial I/O lines
System Compatibility	Honeywell TDC 3000, IPC 620/621
Function	Controls the serial I/O card file and links to 621-9939 SLM
Redundancy	Supports redundant and nonredundant configurations
Termination	Requires 200–300 Ω terminating resistors at extreme ends of the serial channel
Dimensions	33 × 23 × 13 cm (approx.)
Weight	1.85 lbs (0.84 kg)
Warranty	12 months
Redundant Communication	Dual-port design ensures high reliability in redundant serial I/O configurations
Flexible Deployment	Can be used in both redundant and nonredundant applications
Industrial Reliability	Built for mission-critical Honeywell DCS environments
Protocol Support	Interfaces with multiple serial-based field devices including sensors, actuators, HMIs, and printers
Diagnostics	Front-panel LEDs provide real-time status and fault indicators for easy monitoring
Seamless Integration	Works directly with 621-9939 Serial Link Module for processor communication
Manufacturer	Honeywell
Model / SKU	621-9938

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Ships within 24 hours | 12-Month Warranty | Worldwide Delivery

Category: cpu main processors safety systems dcs systems all sensors transducers communication modules hmi displays honeywell condition monitoring

Honeywell 621-9938

Honeywell 621-9938 Serial I/O Module. Serial I/O Module. Genuine Honeywell. Live-rack tested, 48h burn-in. 12-month warranty. Ships within 24h.

Compatible Parts — Same System

These modules share the same system family as the 621-9938. Commonly ordered together for complete rack builds or spare parts kits.

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