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Hardware
Types 1 and 2 cable must be used with data connectors (also known as
IEEE 802.5 Medium Interface Connectors) because of the need to
terminate the cable shielding. Types 1 and 2 cable and data connectors are
available from IBM distributors and from other suppliers such as Belden
or Alpha.
Type 1 Cable (Data Connector Modules)
Standard non-plenum and plenum IBM Type 1 cables should be used with
LAUs equipped with data connectors. Recommended wire gauge is 22
AWG. The following requirements should be met:
•
Solid copper in two pairs
•
A maximum DC resistance of 17.4 ohms per 1000 feet
•
Characteristic impedance of 150 ohms at 3-20 MHz
•
Maximum attenuation per 1000 feet
— 7 dB at 4 MHz
— 14 dB at 16 MHz
•
Maximum continuous current per conductor at 2.3 amp
•
UL specification
— UL Type CM (non-plenum)
— UL Type CMP (plenum)
•
Beldfoil shield type at 100% coverage
•
Data connector model number ADC-205
Cable Lengths
The maximum lengths of the cables that connect the attaching devices to
the LAU port Channels and the Main port of the LAU to a MAU lobe port
depend on the data rate (4 or 16 Mbps), the type of token ring device, and
the type of port from which the cable is connected. See Section 3.1,
Installation Background.
12
Lobe Access Unit User's Guide
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