Product Overview

  • Compatible with the baseband ARCNET® network
  • Supports either 2 or 3 ports
  • Panel-mount or DIN-rail mount
  • Configurations available for either link, repeater or hub operation
  • Supports coaxial, twisted-pair and fiber optic cabling
  • LED indicator identifies reconfiguration of the network
  • Minimizes bit jitter with precision delay line timing
  • Watch-dog timer prevents hub lockup
  • Hub unlatch delay digitally controlled
  • Wide-range, low-voltage AC-or DC-powered
  • Provision for redundant power sources
  • Variable data rates from 78 kbps to 10 Mbps
  • Works with all Contemporary Controls Network Interface Modules (NIMs) and active hubs
  • Accommodates AC- or DC-coupled EIA-485 networks

Product Details

The ARCNET Interconnect (AI) Series of fixed-port hubs were created to fill the need to expand ARCNET Local Area Network (LANs) by way of repeaters, links and hubs. Repeaters can extend a network using the same cabling technology. A link can mix two cabling technologies-functioning as a media converter. A hub can add a segment and give support for distributed star topologies. The AI can implement all three of these expansion methods depending upon the number of its ports. The AI2 provides two ports for repeater and link applications while the AI3 implements the hub function. However, the AI2 and AI3 utilize the same robust hub timing electronics found in Contemporary Controls MOD HUB of modular active hubs.

The AI operates from either wide-range, low-voltage AC (8-24 VAC) or DC (10-36 VDC) power. Redundant power sources can be attached for critical applications.

The AI Series supports variable data rates from 78 kbps to 10 Mbps to accommodate the newer ARCNET controller chips and popular EIA-485 transceivers. A watchdog timer stops hub lockup-eliminating the necessity of cycling power due to signal transmission error.

Active hubs increase the robustness of ARCNET networks. They maximize the distance that can be attained on each cable segment-up to 2000 feet (610 m) on coaxial segments and 6000 feet (1825 m) on multimode fiber optic segments. They block interference to the network by squelching reflections caused by open or shorted cable segments attached to the hub. Unused hub ports need not be terminated. Active hubs allow for a distributed star topology; thereby, minimizing the cabling required in a plant. Links and repeaters provide extensions to bus systems or bridging to other cable media.

Each AI port has an LED to indicate the reception of data or the passing of the token. One LED on this unit indicates that the device is operating properly while another indicates the occurrence of a network reconfiguration.

Ordering Information

The AI2 and AI3 series has been discontinued. Limited quantities of the models listed below are still available. Please contact your regional office for replacement options.


Model Description    
AI2-TPB Twisted-pair bus repeater   Contact Us


Model Description    
AI2-485/FOG-ST DC-coupled EIA-485 to fiber optic link   Contact Us


Model Description    
AI3-CXS Coaxial star hub   Contact Us
AI3-FOG-ST/485 Fiber backbone to DC-coupled EIA 485   Contact Us
AI3-FOG-ST/TB5 Fiber backbone to twisted-pair bus hub   Contact Us


Model Description    
AI-XFMR Wall-mount plug-in transformer 120 VAC (nom) input/24 VAC (nom) output (details...) $39
AI-XFMR-E Wall-mount plug-in transformer 230 VAC (nom) input/24 VAC (nom) output (details...) $55
BNC-TER 93 ohm BNC terminator $8
BNC-T BNC "T" connector $8
TB5-TER 100 ohm RJ-45 terminator $8
TPB-TER 100 ohm RJ-11 terminator $8
MDR-20-24 24VDC 20W DIN RAIL POWER SUPPLY (details...) $40
MDR-40-24 24VDC 40W DIN RAIL POWER SUPPLY (details...) $50
SDR-75-24 24VDC 75W DIN RAIL POWER SUPPLY (details...) $90