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Thick Net Cable Notes
This document contains installation recommendations and cabling
guidelines. For more information on thick Ethernet cabling, contact
your local network supplier or call the IEEE (800-678-IEEE).
The EtherExpress™ adapters have a 15-pin, D-shaped AUI connector.
AUI cabling is also known as thick Ethernet, transceiver cable, drop
cable, or 10BASE-5.
Installation Recommendations
After attaching the cable, close the sliding latch on the AUI connector.
This prevents the cable from falling off and disrupting communication
between the computer and the network.
Cabling Guidelines
Use AUI cable conforming to the 10BASE-5 specification. For example,
Belden 9898 works well.
Thick ethernet is a linear bus topology that uses a COAX cable. If
their is a break in the cable, the entire segment will be disrupted.
The thick ethernet COAX cable is usually brightly colored - yellow or
blue. It has "tap" markings every 2.5 meters. (These marks show where
to connect transceivers.)
Workstations are connected to a thick Ethernet cable through the AUI
port on the adapter, a "drop" cable (sometimes called a transceiver
cable) and a transceiver (or MAU).
A thick ethernet cable must be terminated at each end (50ohm
terminators), and one end must be earth grounded. The internal coax
shield must not make electrical contact with the earth ground.
| Cable Lengths |
|
| Max trunk length |
500 meters (1640 feet) |
| Max number of nodes per trunk |
100 |
| Max number of trunks |
5 (only 3 can have wkst attached |
| Max length of entire network |
2500 meters (8200 feet) |
| (all trunks added together) |
|
| Min cable length between taps |
2.5 meters (8 feet) |
| Max length of drop cable |
50 meters (164 feet) |
Up to five trunk segments may be connected (through repeaters), but only
three of these segments can have workstations attached. Repeaters count
as a workstation so if you have two repeaters on a segment then the
maximum number of user workstations is 98.
Example:
Pin name and function:
- Control-in Shield. The shield for the CI twisted pair on the AUI
cable.
- Control-in Circuit A. The positive signal for the CI circuit. This
circuit sends the mau_available and signal_quality_error messages
to the equipment.
- Data-out circuit A. The positive signal for the DO circuit.
- Data-in Shield. The shield for the DI twisted pair in the AUI
cable.
- Data-in Circuit A. The positive signal for the DI circuit.
- Voltage Common. The ground return for the VP circuit.
- not connected
- not connected
- Control-in Circuit B. The negative signal for the CI circuit. This
circuit sends the same signals as listed under pin 2.
- Data-out Circuit B. The negative signal for the DO circuit.
- Data-out Shield. The shield for the DO twisted pair in the AUI
cable.
- Data-in Circuit B. The negative signal for the DI circuit.
- Voltage Plus. The power supply to the transceiver. The supply
must remain in the range of 12V - 6% to 15V + 5%.
- Voltage Shield. The shield for the VC and VP (pins 6 and 13)
twisted pair.
- not connected
This applies to:
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