Siemens ADVANCE NETWORK COMMUNICATIONS BOARD/DATANET 2000592-001 - Manual (Page 57)

ANCB Description, Continued
Jumper J2 Settings The ANCB provides a set of impedance matching jumpers to simplify the
cable interfacing process. Jumper J2 is a six-position header used to
select the proper cable impedance matching circuit for each ANCB
DataNET port. Jumper J2 is logically partitioned into two groups of three
positions, see Figure 4-1. There are two jumpers provided on J2. The
lower jumper configures Port1 and the upper configures Port2. Each
jumper can be placed in one of three positions, see Figure 4-1. The three
positions match cable impedance of 100, 120, and 150 ohms. If the
characteristics of the cable you are using are unknown check with the
cable manufacturer for the resistance setting. The manufacturer’s name
is usually printed on the cable cover.
Connector J5 Connector J5 is the impedance matching jumper for the 10Base2 (BNC)
connector labeled P1 on the ANCB board. The connector is a 2-position
(4-pin) connector. Pin 1 is denoted by a dog-ear that is silk-screened in a
rectangle near J5. The pins are numbered 1 to 4 in the clockwise
direction.
End point devices should be terminated with a 50-ohm resistor. Impedance termination for
Ethernet 10Base2:
Devices that are not on the end point require no termination resistors.
When the 10Base2 connector is not in use (i.e. no cable connected) the
connector should be terminated with a 25-ohm resistor to prevent
spurious errors from being generated on the 10BaseT connector. This is
necessary since both the 10Base2 and 10BaseT connectors are
connected to the same Ethernet Hub chip on the ANCB board.
2000592-001 Troubleshooting
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