COM20051 Datasheet, PDF (70/82 Pages) List of Unclassifed Manufacturers – Integrated Microcontroller and ARCNET (ANSI 878.1) Interface

CABLING THE COM20051
The COM20051 supports several types of cables
and cable interfaces in either bus or star
topologies. The following is a list of
media transceivers, supported media, and
supported topologies:
ALLOWED
TRANSCEIVER TOPOLOGIES
HYC9068
Star only
HYC9088
Bus or Star
RS-485
Bus
MAX.
DIST.
2000ft.
1000ft.
(Coax)
400ft.
(TP)
900ft.
MAX.
NODE
N/A
8
10
32
Isolated
RS-485
Bus
700ft.
12
Fiber-Optic
Star
3Km
N/A
ISOLATION
VOLTAGE
<500V
<500V
15V
D.C.
Coupled
2.5KV
>2.5KV
SUPPORTED
MEDIA
Coax
Coax
Twisted
Pair (TP)
Twisted Pair
Twisted
Pair
Fiber
Note: The above figures are for a 2.5 Mbps data rate. Changing the data rate can significantly
increase or decrease the line length and node count.
For more information please refer to TN7-5 RS-485 Cabling Guidelines for the COM20020 Universal
Local Area Network Controller (ULANC) and Experimental Procedure for Verifcation of RS-485 Cabling
Guidelines or Cabling Alternatives for the COM20020, COM90C66, and COM90C165.
Compatability Considerations
Compatability with existing ARCNET installations
is of importance to some designers. The
COM20051 is compatible with older ARCNET
installations when it is operated in dipulse
mode at 2.5 Mbps using normal
timeout values. It is suggested that the
HYC9068 or HYC9088 transceivers be used to
maintain compatability. The COM20051 is not
compatible with standard ARCNET systems
when the device is used in backplane mode,
when the reduced timeout features are enabled,
or at data rates other than 2.5 Mbps.
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