Honeywell 621-9940 Description Description Honeywell Serial I/O Module (8/16/32 Point) Related products HONEYWELL 620-3691C HONEYWELL 621-3550 HONEYWELL 620-1690 HONEYWELL 621-9934 HONEYWELL 620-3590 HONEYWELL DM106-0-A-00-0-R-1-00000-000-E0