Cabletron Systems CSX1000 - Manual (Page 39)

Workgroup Remote Access Switch 39
H ARDWARE O VERVIEW
System Platforms
The two connectors available for LAN access are the AUI Ethernet and the 10Base-T. Only one of
the two ports may be activated at a time. If you attempt to use both, the system hardware
automatically defaults to the 10Base-T port. Note that the AUI port has a slide-latch mechanism to
lock that connection into place.
The back panel also provides connectors for BRI lines. Depending upon platform option,
connectors are available for one, two, or four BRI lines (providing from two to eight connections).
These lines are identified by the numbers 1 through 4 stamped on the plate adjacent to the port. The
plate can be removed by taking out the two screws. Underneath this plate are one, two, or four pairs
of DIP switches (again, option dependent). These switches control the terminating resistors for the
Basic Rate Interface and should be set in the same direction. If the switches are UP, the switches are
“on,” meaning the resistors for the connector are providing termination for the BRI line. In the
event that both switches are not set in the same direction, improper operation may result. Note that
the system is shipped with the switches activated (ON). For further clarification, refer to the
following illustration.
For all types of connections, there must be terminating resistors at each end of the line. For a Point-
to-Point connection, the 1000 platform is at the end of the line, so these DIP switches must be ON
to provide proper termination. In a Point-Multipoint connection, DIP switch settings are dependent
upon the physical configuration of the line. If the 1000 platform is at the end of the line, the
terminating resistors should be activated (DIP switches ON). If another device at the end of the line
is providing termination, the 1000 platform’s terminating resistors should be deactivated (DIP
switches OFF).
ON
1 2 3 4
Screws which secure plate
BRI port, plate on:
BRI port, plate off:
line 4 switches line 3 switches line 2 switches line 1 switches
If both switches in pair are in UP position, switches are ON.
switches 3&4 control line 1 (ON in illustration)
switches 1&2 control line 2 (ON in illustration)
For the B2 platform option, switches 3&4 control line 1;
switches 1&2 are not used.