INSTALLATION
1. Installation of the AT-280 and AT-480 is as simple as connecting the AUI
drop cable from the Ethernet transceiver into the female connector located
at the top of the AT-280 or AT-480 fanout.
2. Attach additional AUI cables to the male AUI connectors and run them to the
workstation or DTE. Only one AUI connection is necessary to power the
AT-280 and AT-480 fanouts.
3. Power ON the DTE and check that the power indicator on the AT-280 and
AT-480 is lit.
4. Now check that packets can be transmitted and received from the DTE to a
host located on the network.
The IEEE 802.3 specification states that the maximum length of an AUI cable
must not exceed 50 meters (164 ft.) For network reliability, these limits should not
be exceeded.
INTRODUCTION
This user manual covers the installation and troubleshooting of the CentreCOM
Multiport Transceivers. If you encounter any problems or questions on the follow-
ing procedures, call the Technical Support Department at (206) 821-2056 or fax
(206) 821-6361. Read these instructions thoroughly before stating assembly.
The AT-280 and AT-480 transceivers are IEEE 802.3 compliant 10BASE5 trans-
ceiver Media Attachment Unit (MAW) fanouts. The AT-280 is a two port while the
AT-480 is a four port transceiver fanout. Except for the number of ports, the two
model function identically. These Ethernet transceiver fanout devices are powered
by a Data Terminal Equipment (DTE) attached to any of the male Attachment Unit
Interface (AUI) connections. Their function is similar to other multiport fanouts
operating in the remote mode in that a transceiver MUST be attached to the 15 pin
female AUI connection located at the top of the fanouts.
PREPARATION
SQE Test or Heartbeat
The AT-280 and AT-480 fanouts do not generate the Signal Quality Error (SQE)/
Heartbeat Test signal. If the a DTE to which the AT-280 or AT-480 is connected
requires the SQE/Heartbeat function then place the SQE Test switch located on
the external transceiver to the ON position.
Heartbeat and Repeaters
Many times Ethernet repeaters do not want the Heartbeat function and, in fact,
may cause excessive collisions if Heartbeat is enabled. It is recommended that
the Heartbeat function is on the external transceiver is disabled whenever an
AT-280 and AT-480 is connected to a repeater unit.