ARCnet installation

Installing the Network

ARCnet is an extremely easy-to-install LAN since it offers a flexible topology with few limitation. It can be configured as a simple Star or Bus topology network, or a Combined Star and Bus topology network.

The ARCnet card is equipped with a standard BNC female connector (see figure below) for connection to RG-62 A/U coaxial cable.

Star Topology Network

To install a star network, here are the hardware requirements.

ARCnet Card: The ARCnet network card must have a low impedance driver hybrid (SMC 9068).
A low impedance hybrid is equivalent to a high impedance driver hybrid and terminator.
Cable: The ARCnet network uses the RG-62 A/U 93-ohm coaxial cable with BNC male connectors at both ends. It is used to connect a network station, Passive Hub or Active Hub.
Passive Hub: The Passive Hub has four ports with four BNC female connectors to connect a network station or Active Hub. It is used to relay network signals. Any unused port on the Passive Hub must be terminated with a 93-ohm BNC Terminator.
Active Hub: The Active Hub consists of eight ports with eight BNC female connectors to connect a network station, Passive Hub or Active Hub. It is used to relay network signals and amplify network signal strength. It is recommended that any unused port on the Active Hub be terminated with a 93-ohm BNC Terminator, however, it is not required.
BNC Terminator: The BNC Terminator is equipped with a 93-ohm resistor and is usually installed on the Passive or Active Hub. It is used to prevent the network transmissions from being interfered by reflections.

Installation Rules

While the ARCnet has been designed for maximum flexibility and ease of installation, the installation rules for a star topology network layout using low-impedance network cards must be borne in mind and are detailed below:

A Passive Hub is mainly used as intermediate connections between stations and Active Hubs. To connect Passive Hubs in series is not allowed since the Passive Hubs only relay network signals but cannot strengthen the signals, otherwise the signal will be too weak to transmit data.
Any unused port on the Passive Hub must be terminated with a 93-ohm BNC Terminator.
Maximum distance between a Passive Hub and a station: 30 meters (100 feet)
Maximum distance between a Passive Hub and an Active Hub: 30 meters (100 feet)
An Active Hub can be connected to stations, Passive Hubs, and another Active Hubs.
Maximum distance between an Active Hub and a station: 600 meters (2,000 feet)
Maximum distance between Active Hubs: 600 meters (2,000 feet)
It is recommended that any unused port on the Active Hub be terminated with a 93-ohm BNC Terminator, but it is not required.
Maximum distance from one end of the network to the other end: 6,000 meters (20,000 feet)
Do not create a loop, i.e., a cable coming from a hub travels through other hubs and connects back t the original hub.

Bus Topology Network

The bus ARCnet network uses a common bus line called Trunk Cable to link stations together. The Trunk Cable can consist of one or many Segments. A Segment is defined as a cable length consisting of a number of Sections, and terminated at each end by a BNC Terminator. Every two segments are linked together via an Active Link. A Section refers to the cable length between two Tee-connectors (stations).

To install a bus network, here are the hardware requirements.

ARCnet Card: The ARCnet network card must have high-impedance driver hybrid (SMC 9058).
Tee-Connector: The Tee-Connector contains one BNC mate connector (to connect to ARCnet card), and two BNC female connectors (to connect to a cable or BNC Terminator).
Cable: The ARCnet network uses the RG-62 A/U 93-ohm coaxial cable with BNC male connectors at both ends. It is used to connect two network stations or an Active Link.
BNC Terminator: The BNC Terminator is equipped with a 93-ohm resistor and is usually installed on the active hub or at the end of a bus network segment. It is used to prevent the network transmissions from being interfered by reflections.
Active Link: The Active Link has two ports with two BNC female connectors to connect two bus network segments.

Installation Rules

While the ARCnet has been designed for maximum flexibility and ease of installation, the installation rules for a bus topology network layout using high-impedance network cards must be borne in mind and are detailed below:

Connect a station to a cable via a Tee-connector.
Do not use any cable between a station and a Tee-connector.
It is not allowed to use the Passive Hubs on a bus topology network.
Minimum distance (section) between two Tee-connectors: 1 meter (3 feet)
Maximum number of stations in a bus network segment: 8
Maximum distance of a bus network segment: 300 meters (1,000 feet)
Both ends of a bus network segment must be installed with a 93-ohm BNC Terminator or an Active Hub.
Maximum distance from one end of the network to the other end: 6,000 meters (20,000 feet)
Do not create a loop, i.e., a cable coming from a hub travels through other hubs and connects back to the original hub.

Combined Star and Bus Topology Network

The Combined Star and Bus Topology Network refers to the network layout using the low-impedance and high- impedance ARCnet network cards on the same network.

To install a combined star and bus topology network, you should have the combinations of hardware requirements for star and bus networks as described previously.

Installation Rules

In addition to the installation rules for star and bus networks listed in earlier sections, the installation rules for a combined star and bus topology network layout must be observed.

A bus network and a star network can be combined on the same network by using an Active Hub.
A bus network card (high-impedance) may be connected to a hub in place of a low-impedance ARCnet network card in a star network.
The low-impedance ARCnet network cards are not allowed to place in the middle of a series of high-impedance ARCnet network cards. They can, however, be placed at the end of a cable segment instead of a terminator.

ARCnet and SMC are registered trademarks.